Biogeochemical Cycle

Q.

For the given assertion and reason, choose the correct option.

Assertion[A]: Fungi are saprophytic organisms.
Reason[R]: They feed on dead and decaying organisms for nutrition.

1. Both A and R are correct; R explains A

2. Both A and R are correct; R does not explain A

3. Both A and R are incorrect

4. A is correct but R is incorrect

Q.

Which mode of nutrition is found in bacteria and fungi?

1. Swallowing

2. Licking

3. Filtering

4. Biting

Q.

Starting point of a food chain is always a ___.

1. plant

2. animal

3. both plant and animal

4. none of the above

Q.

Humans are:

1. Autotrophs

2. Heterotrophs

3. Saprotrphs

4. Decomposers

Q.

Nearest and richest source of raw material for plants is :

1. Water

2. Soil

3. CO₂

4. Air

Q. What is ecosystem? Which are its different components?

Q.

Where do non-green organisms such as fungi and bacteria obtain their nourishment from?

1. None of the above

2. Only water and soil nutrients

3. Decaying organic matter

4. Light independent phase

Q.

The biogeochemical substances are never lost in the biogeochemical cycle. They are only recycled.

1. True

2. False

Q.

In the depths of the Pacific and Atlantic Oceans, there exist hydrothermal vents that throw out toxic sulfur chemicals like Hydrogen sulfide and super hot water into the ocean. Some bacteria use these compounds to make their own food and store energy. The heat and sulfur compounds are generated by hot molten rock under the earth’s crust.

What kind of organisms are these bacteria?

1. Autotrophs

2. Heterotrophs

3. Saprotrophs

4. Decomposers

Q.

Transpiration plays significant role in SPAC (Soil Plant Atmosphere Continuum).

1. True

2. False

Q. In the communities found deep in the ocean off the shore of Japan, bacteria have special enzymes that allow them to form organic matter by chemosynthesis. These communities frequently have worms, clams, shrimp and many other organisms clustered together. These communities nestle around hydrothermal vents where super heated water, springs from the bottom of the ocean. In hydrothermal vent communities, we would not expect to find:

1. carbon compounds
2. producers
3. chemosynthesis
4. chlorophyll

Q.

Explain why respiration is said to be the reverse of photosynthesis.