18. In a clinical trial with an active control, what is the experimental treatment being compared to ?
O A A medicine with known effect in the disease being studied
O B. An experimental treatment for the disease being studied
O C. Nothing
OD. A placebo

Answers

Answer 1

Answer: a medicine with known effect in the disease being studied

Explanation:


Related Questions

the effects of toxic chemicals are minimized by which following three mechanisms

Answers

Answer:

Metabolic degradation, excretion, and repair.

Explanation:

need the answer asap!!

Answers

Answer:

Cell division, as this includes meiosis and mitosis, which are types of asexual reprodcution

Explanation:

The Earth's magnetosphere is created by: A. a fusion in Earth's core
B. spinning in the Earth's core
C. gravity in the Earth's core
D. too much heat in the Earth's core​

Answers

Answer:

solar wind

The magnetosphere is the region of space surrounding Earth where the dominant magnetic field is the magnetic field of Earth, rather than the magnetic field of interplanetary space. The magnetosphere is formed by the interaction of the solar wind with Earth's magnetic field.

All of the following factors can cause famines except
А
the failure of food production to keep pace with population growth
B.
distribution problems caused by political turmoil
С
new, higher-yield crops
D
crop failure brought on by sustained drought

Answers

Answer:

C: new, higher-yield crops

Explanation:

All of the other answers are problems while C is a positive scenario.

describe the three general methods used by ecologists to study organisms

Answers

Answer: The three main research methods used are observation, modeling, and experimentation.

Explanation:

Observation:

Every experiment requires observation. Ecologists must observe the environment, the species within it, and how those species interact, grow and change. Different research projects different types of assessments and observations.

Ecologists sometimes use a desk-based assessment, or DBA, to collect and summarize information about specific areas of interest. In this scenario, ecologists are using information already collected from other sources.

Oftentimes, however, ecologists rely on observation and fieldwork. This entails going into the habitat of the subject of interest to observe it in its natural state. By doing field surveys, ecologists can track the population growth of species, observe community ecology in action and study the impact of any new species or other introduced phenomena in the environment.

Each field site will differ in nature, shape, or other ways. Ecological methods allow for such differences so that different tools can be used for observations and sampling. It is crucial that sampling be done randomly to combat bias.

Modeling:

Ecological methods rely heavily on statistical and mathematical models. These provide ecologists with a way to predict how an ecosystem will change over time and react to changing conditions in a system.

Modeling also provides another way to decipher ecological information when fieldwork is not practical. There are several drawbacks to relying solely on fieldwork. Because of the typically large scale of fieldwork, it is not possible to replicate experiments exactly. Sometimes even the lifespan of organisms is a rate-limiting factor for fieldwork. Other challenges include time, labor, and space.

Modeling provides a method in which to streamline information more efficiently.

Examples of modeling include equations, simulations, graphs, and statistical analyses. Ecologists use modeling for producing helpful maps as well. Modeling allows for calculations of data to fill in gaps from sampling. Without modeling, ecologists would be hampered by the sheer amount of data that needs to be analyzed and communicated. Computer modeling allows for comparatively rapid analysis of data.

A simulation model, for example, enables the description of systems that would otherwise be extremely difficult and too complex for traditional calculus. Modeling allows scientists to study coexistence, population dynamics, and many other aspects of ecology. Modeling can help predict patterns for crucial planning purposes, such as for climate change.

Humanity’s impact on the environment will continue. It, therefore, becomes ever more crucial for ecologists to use ecological research methods to find ways to mitigate the effects on the environment.

Experimentation:

The overarching purpose of ecological methods for research is to get high-quality data. Experiments must be carefully planned.

Hypothesis: The first step in any experimental design is to come up with a hypothesis or scientific question. Then, researchers can come up with a detailed plan.

Factors that affect fieldwork experiments include the size and shape of an area that needs to be sampled. Field site sizes range from small to very large, depending on what ecological communities are being studied. Experiments in animal ecology must take into account the potential movement and size of animals.

For example, spiders would not require a large field site for study. The same would be true when studying soil chemistry or soil invertebrates. You could use a size of 15 meters by 15 meters.

Herbaceous plants and small mammals might require field sites of up to 30 square meters. Trees and birds might need a couple of hectares. If you are studying large, mobile animals, such as deer or bears, this could mean needing a quite large area of several hectares.

Deciding upon the number of sites is also crucial. Some field studies might require only one site. But if two or more habitats are included in the study, two or more field sites are necessary.

Tools: Tools used for field sites include transects, sampling plots, plotless sampling, the point method, the transect-intercept method, and the point-quarter method. The goal is to get unbiased samples of a high-enough quantity that statistical analyses will be sounder. Recording information on field data sheets aids in the data collection.

A well-designed ecological experiment will have a clear statement of purpose or question. Researchers should take extraordinary care to remove bias by providing both replication and randomization. Knowledge of the species being studied as well as the organisms within them is paramount.

Results: Upon completion, collected ecological data should be analyzed with a computer. There are three types of ecological experiments that can be made: manipulative, natural, and observational.

Hope This Helps!

The 3 general methods used by ecologists to study organisms include:

ObservationModellingExperimentation

Observation involves observing organisms in their natural habitats or environments and then recording the findings. It is usually done by field surveying.

The different species living in an environment, how they interact with each other and other abiotic components of the environment are some of the observations taking during field surveys. The growth of individual species, the effects of introducing new species, their adaptations and other areas of community or ecosystem ecology can be studied through observation.

Modelling requires a simulation of real-life ecological processes through  different manipulations. This could be done in the laboratory, on the field, or even on the computer. Computer modelling requires that data from observation or experimentation are supplied as input and the inputs are subject to mathematical maneuvering.

With models, complex ecological processes can be simulated and analyzed and extrapolated to deduce how things might happen in real life ecological interactions.  

Experimentation involves setting up experiments following the scientific method. It can be a observational or controlled experiments.

Observational experiments requires studying organisms, populations, communities, or ecosystems through pure observation without changing or manipulating any variable.

Controlled experiments requires that variables are introduced and manipulated in some groups while some groups serve as the baseline without any manipulated variables.

Data are obtained from experiments and these are analyzed in relevant ways to support or reject hypotheses.  

More on ecological studies can be found here: https://brainly.com/question/22875048

How do I know how much energy is availably in each level of the energy pyramid?

Answers

Answer:

What Exactly Do Energy Pyramids Have to Do With Energy? Energy pyramids show a very cool trend: Each level only gets 10% of the energy from the level below it.

Explanation:

Move this lichen
to where it belongs within the process of primary succession


Pls help 15 points

Answers

Answer:

1

Explanation:

Lichen are usually the first thing to grow on bare rock, making them a pioneer species. Fun fact, you can use lichen to determine if the air quality in an ecosystem is polluted.

Hope this helped :)

which of tge following is true about Earth's temperatures?​

Answers

Answer:

Water vapor and clouds are the major contributors to Earth's greenhouse effect

Explanation:

are atrophies considered producers or decomposers

Answers

Answer:

decomposers

Explanation:

HELP ASAP PLZ PLZ


Would the crater size for an impact crater change if it was dropped from 6 meters (18 ft)? Why or why not?

Answers

Answer:

yes it would change

Explanation:

lots of factors can contribute like acceleration distance and resistance.


which part of Earth is not influenced by energy from the sun?

Answers

Answer: Mantle

Explanation:

Submit your project researching some environmental problems caused by the agriculture and natural resource industry. Be sure your
essay includes the following:
• the name of the article, author, and publisher or site owner;
• a description of the problem;
• a discussion of how it relates to agriculture or natural resources;
• a discussion of potential solutions to the problem; and
• a discussion of your own ideas on the causes of and solutions for the problem.
Ok

Answers

Answer:

this is what i put, i tried my best and im sorry its not the greatest but maybe it can help some of you out and give you some ideas.

Agriculture is the leading source of pollution in many countries. Pesticides, fertilizers, and other toxic farm chemicals can poison fresh water, marine ecosystems, air, and soil. They also can remain in the environment for generations.

What are the major environmental problems caused by agriculture?

Agriculture contributes to a number larger of environmental problems that cause environmental degradation including climate change, deforestation, biodiversity loss, dead zones, genetic engineering, irrigation problems, pollutants, soil degradation, and waste.

Humans impact the physical environment in many ways: overpopulation, pollution, burning fossil fuels, and deforestation. Changes like these have triggered climate change, soil erosion, poor air quality, and undrinkable water.

Fossil fuels began to be used, which led to increased pollution, and the construction of factories led to the loss of habitat for many wild animals. The development of agriculture has led to the emergence of new plant varieties, domestication of animals, and disturbance of soil composition.

Therefore, some of the environmental problems caused by the agriculture and natural resource industry are well described above.

To learn more about Environmental problems, refer to the link:

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Which of the following are steps of the inquiry process?
Check all that apply.
A. Summary
B. Prediction
C. Fabrication
D. Observation
E. Invention
ARNEF. Question

Answers

Answer:

Understand the problem.

Make a plan.

Carry out the plan.

Look back and reflect.

Explanation:

A group of students is learning to identify each organ of the human body by looking at images. The students identify the stomach. Which statement best describes the stomach?
The stomach stores food for energy.
B. The stomach breaks food into small pieces so we can breathe.
C. The stomach carries bits of food to different parts of the body.
D. The stomach breaks food into small particles.

Answers

Answer:

D

Explanation:

The acids in your stomach break down the food you eat

You think that you spot a new planet with your telescope. For the space object to be classified as a planet, you know that it must.

Answers

Answer:

D

Explanation:

An example being our solar system. The planets in out solar system orbit around the sun, which is a star.  I hope this helps, please mark Brainliest!

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Answers

I agree fully!! asdwasdwasdwasdwasdwasdw

What are the characteristics of kingdoms archaebacteria?

Answers

Answer:

Archaebacteria are obligate or facultative anaerobes, i.e., they flourish in the absence of oxygen and that is why only they can undergo methanogenesis.

The cell membranes of the Archaebacteria are composed of lipids.

The rigid cell wall provides shape and support to the Archaebacteria. It also protects the cell from bursting under hypotonic conditions.

The cell wall is composed of Pseudomurein, which prevents archaebacteria from the effects of Lysozyme. Lysozyme is an enzyme released by the immune system of the host, which dissolves the cell wall of pathogenic bacteria.

These do not possess membrane-bound organelles such as nuclei, endoplasmic reticulum, mitochondria, lysosomes or chloroplast. Its thick cytoplasm contains all the compounds required for nutrition and metabolism.

They can live in a variety of environments and are hence called extremophiles. They can survive in acidic and alkaline aquatic regions, and also in temperature above boiling point.

They can withstand a very high pressure of more than 200 atmospheres.

Archaebacteria are indifferent towards major antibiotics because they contain plasmids which have antibiotic resistance enzymes.

The mode of reproduction is asexual, known as binary fission.

They perform unique gene transcription.

The differences in their ribosomal RNA suggest that they diverged from both prokaryotes and eukaryotes.

Answer: Archaebacteria are obligate or facultative anaerobes, i.e., they flourish in the absence of oxygen and that is why only they can undergo methanogenesis.

The cell membranes of the Archaebacteria are composed of lipids.

The rigid cell wall provides shape and support to the Archaebacteria.

Explanation:

Hope this helps :)

4. In a prairie ecosystem, nitrogen and other matter builds up in animal
wastes. Which organisms return this matter to the ecosystem by
breaking down wastes?

Answers

Answer:

Fungi, insects, and earthworms

Explanation:

They decompose wastes, returning nitrogen back to the ecosystem.

Which type of body has a core made of ice, dust, and rock?
A. stars
B.meteors
C. comets
D. asteroids​

Answers

C hope this helped The solid, core structure of a comet is known as the nucleus. Cometary nuclei are composed of an amalgamation of rock, dust, water ice, and frozen gases such as carbon dioxide, carbon monoxide, methane, and ammonia.". In simpler words, comets contain ice, dust, and rocks in its core.

Answer:

C Comets

Explanation:

Large molecules that are built from repeating smaller molecules called
(Insert first answer) are called (insert second answer)

Answers

Answer:

The first answer would be a polymer and the second answer would be a monomer.

The answer to this message would you like you

HELPPP! I WILL GIVE YOU BRAINLIEST!!!

The diagram below shows a food chain.
Grass Rabbit Fox Bear

What would happen if human activity reduced the rabbit population?
A.
The bear population would increase.
B.
The grass population would decrease.
C.
The fox population would decrease.
D.
The fox population would increase.

Answers

Answer:

c, because the fox wouldnt have enough food

Explanation:

Answer:

C. The fox population would decrease.

Explanation:

It's a very direct cause and effect situation. Because the fox is a consumer of the rabbit, the fox would decrease after the rabbit population decrease, the bear would be indirectly affected.

what kind of energy transformation takes place when plants perform photosynthesis to produce glucose molecules​

Answers

Answer:

electrical energy

Explanation:

electrical energy

A generator converts kinetic energy into electrical energy.

Question 17
Identify the organelle by its function
Creates ATP (energy) and known as the powerhouse of the cell.

Answers

the organelle is called the mitochondria
Mitochondria, it’s known as the powerhouse of the cell

The picture below shows the bone structures of whale and bird.

Picture shows similar bone structures of whale and bird.

Based on the diagram, which of these statements is correct about whales and birds? (2 points)

Group of answer choices

They use their limbs to catch their prey.

They move in the same manner.

They have similar food habits.

Answers

I had almost the same question on one of my quizzes but it had one other answer. Mine was,

"The picture below shows the bone structures of whale and bird.

Picture shows similar bone structures of whale and bird.

Based on the diagram, which of these statements is correct about whales and birds?  

 a ) They have similar food habits.

b ) They move in the same manner.

c ) They share a common ancestor.

d ) They use their limbs to catch their prey."

After doing some research, I found that the correct answer was that they share a common ancestor.

Why do plant cells need a cell wall and chloroplasts but animal cells do not?

Answers

Answer:

Plant cell needs cell wall whereas animal cell do not because the plants need rigid structure so that they can grow up and out . ... So animal cells can have various shapes, but plant cells only have the shapes of their cell walls.

Explanation:

Thats because Plant cell needs cell wall whereas animal cell do not because the plants need rigid structure so that they can grow up and out . ... So animal cells can have various shapes, but plant cells only have the shapes of their cell walls.

Bats and birds eating insects at different times of day is an example of (1 point)
O survival of the fittest.
O resource partitioning.
O competitive exclusion.
O natural selection.

Answers

Bats and birds eating insects at different times of day is an example of Resource Partitioning. So, the correct option is B.

What is Resource Partitioning?

Resource partitioning or niche differentiation is a process of natural selection that will force competitors to use resources differently in such a way as to avoid competition between species. Resource partitioning causes the co-existence of species.

If bats and birds eat insects at different times of the day, there is no survival of the fittest. Competitive exclusion states that no two species can co-exist in the same niche for a long time.  

Therefore, bats and birds eating insects at different times of day is an example of Resource Partitioning.

To learn more about Resource Partitioning, refer to the link :

https://brainly.com/question/15686970

Ehlers-Danlos syndrome is a genetic disorder that weakens the binding properties of connective tissues. What would most likely be one of the symptoms of this disorder?
A.
Increased joint mobility
B.
Decreased brain activity
C.
Decreased bone density
D.
Increased muscle size

Answers

Answer:

Increased Joint Mobility

Drag the tiles to the correct boxes to complete the pairs.
Match the characteristics with the phylum.
water vascular system
tentacles with stinging cells
molting for growth
the presence of mantle
Arthropoda
Cnidaria
Molluska
Echinodermata

Answers

Answer:

Water vascular system = Echinodermata

Tentacles with stinging cells= Cnidaria

Molting for growth= Arthropoda

Presence of mantle= Molluska

Explanation:

14. Scientists use models of earthquakes to (5 points)
O change their location
O stop them from occurring
O understand the process
O increase the waves formed in the process

Answers

Stop them from occurring

Answer:

under stand the process

Explanation:

i took the test

goodluck to people taking it

Which is the best way of comparing two or more organisms
A. Homologous structures
B. DNA
C. Vestigial Structures
D. Fossils

Answers

Answer:

its b

Explanation:

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