The area labeled X is known as

A.
an atomic nucleus
B.
an active site
C.
a pH indicator
D.
a temperature regulator
ecule

Answer:

Oxygen makes up about one-fifth the volume of Earth'­s atmosphere today, and is a central element of life as we know it.

But that wasn'­t always the case. Oxygen, although always present in compounds in Earth'­s interior, atmosphere, and oceans, did not begin to accumulate in the atmosphere as oxygen gas (O2) until well into the planet'­s history. What the atmosphere was like prior to oxygen'­s rise is a puzzle that Earth scientists have only begun to piece together.

Earth coalesced a little more than 4.5 billion years ago from bits of cosmic debris. Liquid oceans existed on the planet almost from the beginning, although in all likelihood they were repeatedly vaporized by the massive meteorites that regularly clobbered the planet during its first 700 million years of existence. Things had settled down by 3.8 billion years ago, when the first rocks that formed under water appear in the geologic record. (They exist in what is now southwest Greenland.)

If Earth had water, it must have had an atmosphere, and if it had an atmosphere, it must have had a climate. What was Earth'­s early atmosphere made of? Nitrogen (N2), certainly. Nitrogen makes up the bulk of today'­s atmosphere and likely has been around since the beginning. Water vapor (H2O), probably from volcanic emissions. Carbon dioxide (CO2), also emitted by volcanic eruptions, which were plentiful at that time. And methane (CH4), generated inside the Earth and possibly also by methane-producing microbes that thrived on and in the seafloor, as they do today.

Carbon dioxide, water vapor, and methane played an important role in Earth'­s subsequent development. Four billion years ago, the Sun was 30 percent dimmer, and therefore colder, than it is today. Under such conditions, Earth'­s water should have been frozen, yet clearly it wasn'­t. The water vapor, carbon dioxide, and methane acted as greenhouse gases, trapping heat and insulating the early Earth during a critical period in its development.

Of oxygen, meanwhile, the early atmosphere held barely a trace. What did exist likely formed when solar radiation split airborne molecules of water (H2O) into hydrogen (H2) and oxygen (O2). Hydrogen, a lightweight gas, would have risen above the atmosphere and slowly been lost to space. The heavier oxygen gas, left behind, would have quickly reacted with atmospheric gases such as methane or with minerals on Earth'­s surface and been drawn out of the atmosphere and back into the crust and mantle. Oxygen could only begin to accumulate in the atmosphere if it was being produced faster than it was being removed'—in other words, if something else was also producing it.

That something was life. Although the fossil evidence is sketchy, methane-producing microbes may have inhabited Earth as long ago as 3.8 billion years. By 2.7 billion years ago, a new kind of life had established itself: photosynthetic microbes called cyanobacteria, which were capable of using the Sun'­s energy to convert carbon dioxide and water into food with oxygen gas as a waste product. They lived in shallow seas, protected from full exposure to the Sun'­s harmful radiation. (To learn more about these organisms and the fossil evidence for them, watch the accompanying video "Early Fossil Life.")

Answer:

Adenine(a) and Thymine(t), Cytosine(c) and Guanine(g)

Explanation:

Answer:

Most likely A

Explanation:

As the height (m) increases, the weight (kg) also tends to increase.

Answer:

b

Explanation:

Answer:

1. 0 chance (0%)

2. 2 chances (50%)

3. 4 chances (100%)

Explanation:

the way a punnet square works is that you basically multiply two genes. for example:

    b   b

B Bb Bb  

b bb bb  

then, if it's uppercase, it is dominant. if it's dominant, it will take over the recessive gene. if it was Bo, B being brown and dominant, and o being recessive and orange, then brown would take over. there are also cases with codominant but that's not in the question. feel free to ask me anything about this.

Answer:

The species of Archaeopteryx is lithographica and siemensii

Explanation:

Fun fact: Archaeopteryx is a combination of two ancient Greek words: archaīos, meaning "ancient," and ptéryx, meaning "feather" or "wing." 

Archaeopteryx has long been thought to be the earliest known bird and a transitional form between birds and reptiles.

Many consider Archaeopteryx, which lived approximately 150 million years ago, to be the first bird.

It is actually a transitional species between the birds we see in our backyards and predatory dinosaurs like Deinonychus.

Many features of Archaeopteryx, such as teeth and a long tail, indicate that it evolved from comparatively tiny carnivorous dinosaurs.

It also has a wishbone, a breastbone, hollow thin-walled bones, air sacs in the backbones, and feathers, as do nonavian coelurosaurian relatives of birds.

Archaeopteryx was thought to be the first recognized bird and a transitional form between birds and reptiles for a long time.

Thus, the two groups that are represented in archaeopteryx are birds and reptiles.

For more details regarding archaeopteryx, visit:

https://brainly.com/question/15828307

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Answer:

Substitution!

Explanation:

The researcher substituted GCCATGTT for GCGTACTT. The underlined section is what was changed. Hope this helps!

Answer:

Explanation:

Using renewable energy will always be better than fossil fuels.

This is because fossil fuels need a very long time to renew themselves. And we will run out of them long before they can renew themselves. Besides this, there is a more concerning and very alarming issue with using fossil fuels instead of other energy sources. Global warming and environmental destruction is a very big problem for us in the 21st century. The air is more and more polluted. Temperatures are rising and oceans are rising with them. We will lose the ability to grow food and raise animals in the future if we continue like this.

Answer:

The patient's cells will swell and then burst. The solute concentration outside the cell is lower than inside the cell, so water will move into the cells.

Mike would have to give the patient a hypertonic solution, which will cause water to move out of the cell and the cell to shrink followed by an isotonic solution, which should regulate the concentration inside and outside the cell.

Hope that helps.

Answer:

A) it is moving down the concentration gradient

Explanation:

Brownian motion will cause the molecules (or ions) to spread/diffuse from where they are more concentrated to where they are less concentrated until they are equally distributed in that space (Figure). When molecules move in this way, they are said to move down their concentration gradient.

Answer: B

Explanation:

The independent variable is the experimenter so it changes and controls the dependent variable because it is assumed that the dependent variable gets a direcr effect from the independent variable.

Answer: should be B

Explanation:

Answer:

Evaporation : Liquid --- Gas (Vapor) ; Condensation : Gas (Vapor) --- Liquid

Explanation:

Evaporation is the change of a liquid into gas or vapor, usually by increase in temperature. Eg : Water evaporation into vapors during water cycle, due to sun heat.

Condensation is the change of gas or vapor into liquid, usually by decrease in temperature. Eg : Vapors condensation into water droplets during water cycle, due to lower atmospheric temperature at higher height.

Answer:

Transverse wave, motion in which all points on a wave oscillate along paths at right angles to the direction of the wave's advance. ... Surface ripples on water, seismic S (secondary) waves, and electromagnetic (e.g., radio and light) waves are examples of transverse waves.

Explanation:

hope it helps you.

Answer:

I hope this help's

Explanation:

Answer:

You can find collision zones on the edge of the Pacific Ocean offshore Washington, Canada, Alaska, Russa, Japan, and Indonisa.

Explanation:

Answer:

C.

Explanation:

To calculate the population density, you will divide the population by the size of the area. Thus, Population Density = Number of People/Land Area. The unit of land area should be square miles or square kilometers. You can use square feet or meters if you are finding the density of a smallish space.

Answer:

a on edge

Explanation:

dont trust c i got it 100%

Explanation:

hy i can help you but what we have to do in that pdf

edicted answer - oh! i got that

Answer:

[tex]\huge\boxed{B}[/tex]

Explanation:

You basically have to divide 124 and 3472.

124 ÷ 3472 = 0.0357

0.0357 wolves/mi^2

Therefore your answer would be letter b.

Good luck!~

Answer:

D and A are devently slow My guess would be B or C, since a neon sign usually turn on instantly (or technical within mil a seconds) Its probably the fastest

my guess is C

Answer:

O A. As nutrients increase, the number of life-forms increases.

Explanation:

common sense

The statement that best describes the relationship between nutrients and life forms in an estuary is as follows:

Thus, the correct option for this question is A.

An Estuary may be defined as a type of ecotone that signifies the transitional zone of two different ecosystems which include the freshwater river ecosystem and the marine water ocean ecosystem.

In this ecotone, the characteristics of both ecosystems are present. Hence, it has a high biodiversity as compared to both ecosystems individually. This region shows maximum diversity and is thus known as the edge effect.

This illustrates that when nutrients in the ecotone increase, the number of life forms i.e. biodiversity increases.

Therefore, the correct option for this question is A.

To learn more about Estuary, refer to the link:

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Answer: B- storage place

Explanation:  

Answer:

A

Explanation:

The Calvin Cycle

Once in the mesophyll cells, CO2 diffuses into the stroma of the chloroplast, the site of light-independent reactions of photosynthesis.

Answer:

B and D

Explanation:

Answer: B and D

Explanation:

I took the test

Answer:

Positive:

- offspring are all different, therefore more genetic variations that will increase survival.

- diversity

Negative:

- two partners are involved

- undesirable traits could be inherited by the offspring

I hope this helps I’m sorry I couldn’t think of three for each

Answer: Natural cloning also occurs in animal organisms during processes such as budding (offspring grows out of the body of the parent), fragmentation (the body of the parent breaks into distinct pieces, each of which can produce an offspring), and parthenogenesis. In humans and other mammals, the formation of identical twins is a type of natural cloning.

Explanation:

hope this help from tae lol

Answer: C

Explanation:

Hope this helps

Answer:

c

Explanation:

give them brainliest but i just took the test

and it was right