What was John snows original hypothesis and how did it conflict with prevailing models of Heath and disease

Answers

Answer 1

Answer:

Explanation:Snow's hypothesis was that contaminated water was the source of the disease, but the challenge was how to prove this to others who were skeptical. ... It is now known that cholera is a waterborne disease, spread when water used for drinking or washing food has been contaminated with feces from infected individuals.


Related Questions

In a plant, leaf color and leaf shape are controlled by two linked genes. Leaves of the wild plant are red (R) while a recessive mutation in this gene causes leaves to be white (r). Wild-type leaves are pointed (P), while a recessive mutation in this gene causes them to be smooth (p). For a parent plant that is heterozygous for both traits with both recessive mutations on one chromosome, what genotypes will its gametes be

Answers

Answer:

The genotypes of the gametes are:

RP (parental), rp (parental), Rp (recombinant), rP (recombinant)

Explanation:

Available data:    

Leaf color and leaf shape are controlled by two linked genes.Leaves of the wild plant are red (R) while a recessive mutation in this gene causes leaves to be white (r).Wild-type leaves are pointed (P), while a recessive mutation in this gene causes them to be smooth (p). Parent plant heterozygous for both traits with both recessive mutations on one chromosome

Parent) RP/rp ---> RP are in one chromosome, while rp in another  

                             chromosome

Gametes) RP (parental)

                rp (parental)

                Rp (recombinant)

                rP (recombinant)

Describe what are the roles of producers, Consumers, and decomposers in an ecosystem?

Answers

Answer:

"How might different types of organisms--producers, consumers, decomposers--be important to a healthy ecosystem?" (Producers change energy into matter with chemical energy that other organisms can use and then consumers pass the matter and energy on to other organisms by eating and being eaten; decomposers recycle some ...

Explanation:

Discuss the roles of the enzymes secreted by the pancreas during digestion.

Answers

During digestion, your pancreas makes pancreatic juices called enzymes. These enzymes break down sugars, fats, and starches. Your pancreas also helps your digestive system by making hormones. These are chemical messengers that travel through your blood.

PLSSS MAMM HELP

Fossils cannot tell us anything about living organisms.


Please select the best answer from the choices provided

T
F

Answers

Answer:

false

Hope it will help you.......

The answer is False.

what are the steps in the digestion of protein​

Answers

answer - Protein digestion begins when you first start chewing. There are two enzymes in your saliva called amylase and lipase. They mostly break down carbohydrates and fats. Once a protein source reaches your stomach, hydrochloric acid and enzymes called proteases break it down into smaller chains

Explanation:

Protein digestion begins when you first start chewing. There are two enzymes in your saliva called amylase and lipase. They mostly break down carbohydrates and fats. Once a protein source reaches your stomach, hydrochloric acid and enzymes called proteases break it down into smaller chains of amino acids.

hope it helps!

Science is an attempt to explain
A. the truth concerning all things in Science
B. the supernatural
C. superstitions
D. natural phenomena

Answers

A. The truth concerning all things in science

Answer:

its D i took the k12 test i hope this helps

Explanation:

What are the Complementary DNA base pairs: ATTGGCCTAGC *

Answers

Answer:

taaccggatcg

Explanation:

In hummingbirds feather color is incompletely dominant. A rather large population of hummingbirds has 396 red-sided individuals (RR), 257 brown sided individuals (Re) and 557 tan-sided individuals orr). Calculate the following:_______.
a. What is the allele frequency of the Rallele (o)?
b. What is the allele frequency of the rallele (a)?
Migration season comes and 200 of the red-sided individuals leave the nosulation before mating occurs.
c. After migration season what is the new allele frequency of the Rallele (0)?
d. After migration season, what is the new allele frequency of the rallelelo?
e. Which mechanism of evolution (natural selection, genetic drift, or gene flow) caused the allele frequencies to change?

Answers

Answer:

a) Frequency of the R allele: [(396 x 2) + 257] / (396 x 2) + (257 x 2) + (557  x 2) = 1049 / 2420 = 0.433

b) Frequency of the r allele: [(557 x 2) + 257] / (396 x 2) + (257 x 2) + (557  x 2) = 1371 / 2420 = 0.567

c) Frequency of the R allele: [(196 x 2) + 257] / (196 x 2) + (257 x 2) + (557  x 2) = 649 / 2020 = 0.321

d) Frequency of the r allele: [(557 x 2) + 257] / (196 x 2) + (257 x 2) + (557  x 2) = 1371 / 2020 = 0.679

e) migration is gene flow  

Explanation:

Gene flow (also referred to as gene migration) is the movement of genes that acts to change allele frequencies in local populations by transferring genetic material from one population to another. Gene flow may be caused either by the movement of organisms that reproduce in new populations (migration), or by the movement of gametes (for example, pollen dispersal in plants).

I neeeeeeed help hurrrryyyy

Answers

Answer:

Population

Explanation:

If there's a high death rate then people would want the population to increase because the disease or whatever scenario is killing the people.

I hope this helped and if I'm wrong somebody please correct me :)

I think emigration because deaths would make people wanna leave the country

Choose the mutation that you think is causing Lucy’s ADA enzyme not to work. Form a hypothesis and explain your answer. You can revise your hypothesis as you perform more experiments.

Answers

answer

stop condon mutation

Explanation:

The mutation is defined as the alteration or change in the genetic sequence of the chromosome. The mutations in the ADA genes have been noted and are caused by point mutations.

Point mutations are defined as the mutations in which the alteration of the single nucleotide of DNA occurs.

Stop codon mutations are the type of point mutations, in which the nonsense codons signal the end of protein synthesis.

Adenosine deaminase is involved in purine metabolism. It is involved in the development of the immune system.

Lucy's condition is due to the stop codon mutations in the genetic sequence of the DNA. The stop codon mutation will signal the end of the translation process, which will result in the non-functionality of the ADA enzyme.

Therefore, the stop codon mutation in the ADA enzyme will occur in Lucy's genetic sequence.

To know more about the ADA enzyme, refer to the following link:

https://brainly.com/question/19896249

Megalodon left an awful lot of teeth behind, but don't worry. It is likely that it had plenty of extras. Like modern sharks, Megalodon had several rows of teeth. Scientists believe that Megalodon had six rows of 7-inch-wide, razor-sharp teeth, top and bottom, for a total of 276 teeth in its giant jaws! It's no wonder, then, that this ancient shark left so many of them behind. Without this trail of teeth, we would not know that these enormous creatures swam the ancient oceans as a top predator.Select two sentences from below that best show that the author wants the reader to be able to relate Megalodon's size to everyday life




A.What would you expect a creature whose name means “big tooth” to look like?
B.The Megalodon shark deserves this title.
C.As the Greek roots mega- (“big”) and don (“tooth”) suggest, this awesome prehistoric creature certainly did have huge teeth—as well as a massive and powerful body.
D.Scientists estimate that these gigantic sharks stretched as long as 60 feet.
E.If you're having trouble imagining that, just think of a school bus, typically about 45 feet in length.
F.Now, imagine a shark just a bit larger than that school bus—with 7-inch teeth.
G.Yes, this ancient fish certainly earned the prefix mega!
H.Since these sharks are extinct, how do we know exactly how huge and powerful the Megalodon shark was?

Answers

The answer is D and F. I did the test

Choose THREE examples that correctly predict the effect of a change on the ecosystem.
А
A decrease in the kangaroo rat population will cause a decrease in the coyote
population
B
A decrease in the desert tortoise population will cause a decrease in the
rattlesnake population
Wc
A decrease in the rattlesnake population will cause an increase in the kangaroo

Answers

Answer:

The answer is option A "A decrease in the kangaroo rat population will cause a decrease in the coyote population"

Explanation:

Climate is a significant ecological impact on environments. Changing Climate influences biological systems in an variety of ways. For example, warming may constrain species to relocate to higher scopes or higher rises where temperatures are more helpful for their endurance.

Environmental change not just influences biological systems and species straightforwardly, it likewise communicates with other human stressors, for example, advancement. Although a few stressors cause just minor effects when acting alone, their combined effect may prompt emotional natural changes. For example, environmental change may worsen the pressure that land improvement puts on delicate water front zones. Also, as of late logged forested zones may get defenseless against disintegration if environmental change prompts increments in substantial down pour storms.

why is energy flow through an ecosystem dependent upon continual energy transformations?​

Answers

Answer:

Organisms must gather energy to survive.

Explanation:

Answer:

food

Explanation:

Which of the following best describes the role of water in photosynthesis?

Answers

Answer: During the process of photosynthesis, six molecules of carbon dioxide and six molecules of water react in the presence of sunlight to form one glucose molecule and six molecules of oxygen. The role of water is to release oxygen (O) from the water molecule into the atmosphere in the form of oxygen gas (O2).

Explanation:

The question is incomplete, the options is gotten from another website.

Here are the options.

Water Is the only source ofprotons for the formatlon of & proton gradlent Water molecules donate elecirons to the electron transport chaln: Water molecules combine wlth stored carbon molecules t0 produce glucose Water Is the terminal electron acceptor for electrons that pass through the electron transport chain;

Water molecules combine wlth stored carbon molecules to produce glucose best describe the Role of water

What is Photosynthesis?

Photosynthesis is the process where gree plants uses light energy from sun with carbon dioxide to produce glucose and water in the presence of chlorophyll.

What is the Role of water in Photosynthesis?

Six molecules of water react with six molecules of carbon molecules to produce glucose.

It form chemical potential around membrane which help in the production of energy.

Therefore, Water molecules combine wlth stored carbon molecules to produce glucose best describe the Role of water.

Learn more on Photosynthesis from the link below.

https://brainly.com/question/3529377.

Monomers linked together to form a polymer could be described as beads in a multicolored necklace. Which statement about monomers is true with respect to the above analogy?

A. Monomers in a polymer could be linked in various ways.
B. Monomers in a polymer are of different types.
C. Monomers in a polymer look different but are structurally similar.

Answers

The answer is B

Monomers linked together to form a polymer could be described as beads in a multicolored necklace because monomer in a polymer are of different types.

many united states weather maps throughout the year will look similar to the one above. which explanation best describes the cause of this phenomenon?

Answers

Answer:

d

Explanation:

because it is?

Which image shows both potential and kinetic energy?
NEED HELP ASAP

Answers

the second image shows it

please give an perfect answer​

Answers

Answer:

a neutral solution? i think

Antimycin A Antimycin A is used in catfish farming: added to the water at 10 ppb, it kills small fish but does not harm catfish. Thus, small fish die out, and catfish get all the resources. When Antimycin A is added to isolated mitochondria, NADH and succinate both accumulate. However, if ascorbate, an artificial redox mediator that transfers electrons to cytochrome c, is added, oxygen consumption is still observed. Which step in the respiratory chain is antimycin A likely to inhibit (1 pt)

Answers

Answer:

Inhibits electron transport chain in mitochondria.

Explanation:

Antimycin A inhibits electron transport chain which leads to the complete halt of electron transport in mitochondria. due to this inhibition of electron transport chain in mitochondria leads to the killing of the fishes except catfish and so the catfish increase in population due to more resources and no competition. this Antimycin A is highly toxic for fishes and kill all fishes if used at the amount of 10 ppb.

PLEASE HELP ME WITH 10 and 11!! :(

Answers

Answer:

Please find the answers to numbers 10 and 11 of the attached image below.

Explanation:

10. This question lists the stages of mitosis namely: prophase, metaphase, anaphase, and telophase. The major events that take place in each of these stages are as follows:

A) PROPHASE:

- the supercoiled chromosomes known as chromatin begins to condense making it visible.

- spindle begins to emerge from the centrosome organelle.

- Nuclear envelope begins to break down in order to expose the chromosomes in the nucleus.

B) METAPHASE:

- The chromosome are aligned at the cell plate i.e. the equator/middle of the cell.

C) ANAPHASE:

- The sister chromatids of each chromosome i.e. replicated chromosomes are pulled apart at the centromere by spindle microtubules to the opposite poles of the cell.

D) TELOPHASE:

- Chromosomes at opposite poles begin to decondense into chromatin.

- The nuclear envelope reforms around the chromosomes

11) Cytokinesis is the process that occurs after mitosis (nuclear division). It is the process whereby the cell whose chromosomes are now separated into opposite poles divide into two. In other words, a cell divides into two in the cytokinesis stage.

Which level of organization is shown in the image? Cell. Tissue. Organ. Organ system. "Cobblestones" is not an option.

Answers

This is adipose tissue.-----tissue level

How do bones grow (explain the process)?

Answers

Answer:

Bones grow in length at the epiphyseal plate by a process that is similar to endochondral ossification. The cartilage in the region of the epiphyseal plate next to the epiphysis continues to grow by mitosis. The chondrocytes, in the region next to the diaphysis, age, and degenerate.

How many steps are involved in the bioremediation process?

Answers

7 possibilities total 3 steps.

What molecule is represented by the molecular model shown below?
O Starch
O Adenosine triphosphate (ATP)
O Glucose
O Adenosine diphosphate (ADP)

Answers

Answer:

adenosine triphosphate (ATP)

Answer:

Adenosine triphosphate (ATP)

Explanation:

ATP has 3 phosphates. Look at the model picture it has 3 P's in it representing 2 phosphates.

Please help!! And thank you!!

Answers

Well, understand it :-

The temperature rises as you get higher in the stratosphere and in the thermosphere.Temperatures decrease as you gain height in the troposphere and the mesosphere.

What are the properties of water that you can observe when transpiration takes place?

Answers

Answer:

When water evaporates through the leaves, a pull is created through the xylem, and water moves back to the leaves. This is known as the transpiration pull.

What kind of features would you expect to find in a transitional
fossil between Ichthyostega and Eusthenopteron?

Answers

Answer:

hope that help you

Explanation:

Fossils or organisms that show the intermediate states between an ancestral form and that of its descendants are referred to as transitional forms. There are numerous examples of transitional forms in the fossil record, providing an abundance of evidence for change over time.

what makes a compound different than a mixture

Answers

Compound are substances which can be formed by chemically combining two or more elements. Mixtures are substances that are formed by physically mixing two or more substances.

What best describes enzymes?

Answers

Enzymes are converted into products by the reactions they catalyze. One enzyme can catalyze many different reactions. ... They are molecules made of amino acids that speed up chemical reactions by lowering the activation energy.

The smallest unit of life is a ,and all organisms have at least one.

Answers

Answer: A cell

Explanation:

Answer:

Cell

Explanation:

It just is. :/

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