Question

Which process fixes carbon (i.e., captures carbon and incorporates it into a living thing)?

A. fire

B. Respiration

C. carnivory

D. photosynthesis

Plants manufacture a wide variety of carbohydrates, oils, and proteins, all of which contain carbon atoms. Where do plants get the carbon atoms?

• A. from water
• B. from soil
• C. from the atmosphere
• D. from sunlight

“Fossil fuels” developed from

• A. Carbon-rich deposits of limestone that went through complex chemical changes.
• B. Pools of sand, gravel, and ground rock that went through complex chemical changes
• C. Plants, algae, micro-organisms, animals, and many other organisms that died, but did not completely decay because conditions were unsuitable for bacteria and other organisms that cause decay. Instead, the undecayed organic matter went through slow chemical changes that resulted in one of the types of fossil fuels.
• D. Dust in the atmosphere that settled down to Earth and was buried. Once buried, pressure changed the layers of particulate matter into natural gas, coal, or petroleum.

Plants capture carbon and incorporate it into organic compounds. By what process is most of this carbon eventually returned to the atmosphere?

• A. Diffusion through leaf stomata.
• B. Belching and flatulence by cattle and other ruminants
• C. Burning
• D. Cellular respiration in living things

Answer 1

1st Question) Which process fixes carbon (i.e., captures carbon and incorporates it into a living thing)?

A. fire

B. Respiration

C. carnivory

D. photosynthesis

1^st Answer)

Among the given options, the answer is option D: “Photosynthesis” .

Reason is explained below:

Here “Photo” means “Light energy” and “Synthesis” means “chemical reaction”.

Photosynthesis is the process where the light energy coming from “Sunlight” is taken by plant and the carbon dioxide is taken from air and water present in soil is clubbed and utilized by plant via a chemical reaction where this is transformed to “Glucose/sugars” and “Oxygen”. This happens step by step. The glucose/sugar is used by plant for its own growth and oxygen is released back into atmosphere.

Here the option A, fire has nothing to do with carbon. So this can be ignored.

Here the option B, Respiration is the process where we take oxygen and releases carbon dioxide. Therefore, carbon dioxide is not captured whereas oxygen is captured. So this can be ignored.

Here the option C, Carnivorous is eating other animals and this has nothing to do with carbon. So this can be ignored.

2^nd question)

Plants manufacture a wide variety of carbohydrates, oils, and proteins, all of which contain carbon atoms. Where do plants get the carbon atoms?

• A. from water
• B. from soil
• C. from the atmosphere
• D. from sunlight

The answer is the option C, “From the Atmosphere”.

Reason is explained below:

Plants absorb carbon atoms from atmosphere or air for growing up their structure i.e. parts like leaves, stems using carbon atoms etc and also for their survival. Plants prepare their own food and they don’t depend upon any others for their food. Plants prepare their food from the process called “Photo synthesis”. Photosynthesis is the process where the light energy coming from “Sunlight” is taken by plant and the carbon dioxide is taken from air and water present in soil is clubbed and utilized by plant via a chemical reaction where this is transformed to “Glucose/sugars” and “Oxygen”. This happens step by step. The glucose/sugar is used by plant for its own growth and oxygen is released back into atmosphere.

Answer is not Option A because, plants absorb water from soil but not carbon atoms. So this option can be ignored.

Answer is not Option B because ,plants don’t get carbon atoms from soil. So this option B can be ignored.

Answer is not option D,plants absorb sunlight for their food preparation process called “Photosynthesis” but they don’t get carbon atoms from sunlight. So this option D can be ignored.

3^rd Question) “Fossil fuels” developed from

• A. Carbon-rich deposits of limestone that went through complex chemical changes.
• B. Pools of sand, gravel, and ground rock that went through complex chemical changes
• C. Plants, algae, micro-organisms, animals, and many other organisms that died, but did not completely decay because conditions were unsuitable for bacteria and other organisms that cause decay. Instead, the undecayed organic matter went through slow chemical changes that resulted in one of the types of fossil fuels.
• D. Dust in the atmosphere that settled down to Earth and was buried. Once buried, pressure changed the layers of particulate matter into natural gas, coal, or petroleum.

The answer is option C mentioned below: Plants, algae, micro-organisms, animals, and many other organisms that died, but did not completely decay because conditions were unsuitable for bacteria and other organisms that cause decay. Instead, the undecayed organic matter went through slow chemical changes that resulted in one of the types of fossil fuels.

Reason for Option C:

Fossil fuels are formed due to very slow decomposition of dead plants or bacteria or animals etc by exposure to sun’s heat and pressure inside earth. This takes many million years to shape up into fossil fuels. Fossil fuels formed are ending up to oil, coal, natural gas. So this is the answer.

The options A,B,D do not follow the process by which fossil fuels are formed. So these options can be ignored.

4th Question) Plants capture carbon and incorporate it into organic compounds. By what process is most of this carbon eventually returned to the atmosphere?

• A. Diffusion through leaf stomata.
• B. Belching and flatulence by cattle and other ruminants
• C. Burning
• D. Cellular respiration in living things

The answer is Option D, Cellular respiration in living things.

Reason is explained below

Cellular respiration in living things means for example we like, the human beings, inhale oxygen and energy for our living. We inhale oxygen and convert the consumed food into energy and during this process carbon dioxide is also produced. This energy is received by entire body for functioning i.e. every cell and during respiration the carbon dioxide generated is exhaled into atmosphere.

In short, humans intake oxygen from plants and release carbon dioxide .This process is called cellular respiration and whereas plants intake carbon atoms and release oxygen for their survival and this process is photosynthesis.

Therefore , carbon is released into air by cellular respiration.

Answer is not Option B, Burning can be ruled out as this is not related with carbon emission into air. So this option can be ignored.

Answer is not Option C, Belching and flatulence by cattle and other ruminants is not related with carbon emission into air.As we know belching and flatulence is part of digestion process in living beings.So this option can be ignored.

Answer is not option A, Diffusion through leaf stomato.”Leaf Stomato” is basically a pore on leaf.i.e stomato is a pore.In plants, stomato releases oxygen into air and absorbs carbon dioxide.Therefore, Diffusion through leaf stomato, is emitting oxygen into air but not carbon dioxide.Therefore this option can be ignored.