Tag: biology

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Multiple choice biology biogeochemical cycles carbon cycling mineral coal carbon cycle

The carbon cycle is the movement of carbon on Earth by the processes of --- and ---- .

  1. Plants and animals

  2. Respiration and photosynthesis

  3. Breathing in and breathing out

  4. Oxygen and carbon dioxide
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Carbon exists in the atmosphere as the compound carbon dioxide. It first enters the ecological food web when photosynthetic organisms, such as plants and certain algae, absorb carbon dioxide through tiny pores in their leaves. The plants then "fix" or capture the carbon dioxide and are able to convert it into simple sugars like glucose through the biochemical process known as photosynthesis. Plants store and use this sugar to grow and to reproduce. Thus, by their very nature as makers of their own food, plants remove carbon dioxide from the atmosphere. When plants are eaten by animals, their carbon is passed on to those animals. Since animals cannot make their own food, they must get their carbon either directly by eating plants or indirectly by eating animals that have eaten plants.
Respiration is the process in which oxygen is used to break down organic compounds into carbon dioxide  (CO2) and water (H2O). For an animal then, respiration is both taking in oxygen (and releasing carbon dioxide) and oxidizing its food (or burning it with oxygen) in order to release the energy the food contains. In both cases, carbon is returned to the atmosphere as carbon dioxide.
So, the correct answer is 'Respiration and photosynthesis'.
Multiple choice biology biogeochemical cycles carbon cycling mineral coal carbon cycle

In the earths crust carbon is found in the form of

  1. Carbonates

  2. Hydrogen carbonates

  3. Petroleum

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In the Earths crust only 0.02% Carbon is found in the form of minerals like carbonates, hydrogen carbonates, coal and petroleum.

Multiple choice biology biogeochemical cycles carbon cycling mineral coal carbon cycle

Burning of fossil fuels affects

  1. Nitrogen cycle

  2. Carbon cycle

  3. Phosphorus cycle

  4. Water cycle
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Carbon dioxide is being added to the atmosphere through two types of processes,
(A) Biological i.e respiration and decomposition release carbon dioxide.
(B) Non biological i.e burning of biomass and fossil fuel release a lot of carbon dioxide. Thus burning of fossil fuels affect carbon cycle of nature
So, the correct answer is 'Carbon cycle'
Multiple choice biology biogeochemical cycles carbon cycling mineral coal carbon cycle

Which of the owing statements regarding the maintenance of carbon cycle in the biosphere are correct?
a. Plant utilize solar energy to convert $CO _2$ and water into cellular materials and produce oxygen that animals consume.
b. Oxygen produced by the plants during carbon assimilation is not a byproduct.
c. Energy used by an animal comes from the oxidation of plant material releasing $CO _2$ that escapes into the atmosphere.
d. All decaying organic matter on the earth is ultimately degraded by molds and bacteria to yield $CO _2$ that escapes into the atmosphere.
Select the correct answer.

  1. $2, 3$ and $4$
  2. $1, 3$ and $4$
  3. $1$ and $2$
  4. $1, 2, 3$ and $4$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Plants utilize solar energy for photosynthesis, converting carbon dioxide and water into cellular material while releasing oxygen, which animals consume. Animals derive energy by oxidizing plant material, releasing carbon dioxide back into the atmosphere, and all decaying organic matter is ultimately degraded by microbes to yield carbon dioxide. Statement 2 is incorrect because oxygen produced is indeed a byproduct of carbon assimilation, making statements 1, 3, and 4 correct.

Multiple choice biology ecology carbon cycling mineral coal carbon cycle

The percentage of carbon in lignite is ______%.

  1. $70\, to \,90$
  2. $60\, to\, 80$
  3. $60\, to\, 90$
  4. $60\, to \,70$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Lignite is brownish-black in color and has a carbon content around   60–70  percent, a high inherent moisture content sometimes as high as $75$ percent, and an ash content ranging from $6–19$ percent.

Multiple choice biology coal, petroleum and petrochemicals carbon cycling mineral coal carbon cycle

The variety of coal having highest carbon content is:

  1. peat

  2. anthracite

  3. bituminous

  4. lignite
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Anthracite is a hard compact variety of coal that has a high lustre. it has the highest carbon content, fewest impurities and the highest calorific content of all types of coal which also include bituminous coal and lignite.