# NCERT Solutions Class 12 Biology Chapter 14 Ecosystem

NCERT Solutions Class 12 Biology Chapter 14 Ecosystem. The NCERT solutions for Class 11 Mathematics have been made by Mathematics teacher of one of the best CBSE school in India. These NCERT solutions have been made to give detailed answers and expanations of the concepts as per NCERT which can be easily understood by the students. Refer to other links also to download mathematics NCERT solutions, worksheets, sample papers and Exemplar Solutions.

Class 12 Biology

NCERT Solutions

Chapter 14 Ecosystem

Question 1: Fill in the blanks.

(a) Plants are called as_________ because they fix carbon dioxide.

(b) In an ecosystem dominated by trees, the pyramid (of numbers) is _________ type.

(c) In aquatic ecosystems, the limiting factor for the productivity is _________.

(d) Common detritivores in our ecosystem are_________.

(e) The major reservoir of carbon on earth is_________.

Question 2: Which one of the following has the largest population in a food chain?

(a) Producers

(b) Primary consumers

(c) Secondary consumers

(d) Decomposers

Decomposers include micro-organisms such as bacteria and fungi. They form the largest population in a food chain and obtain nutrients by breaking down the remains of dead plants and animals.

Question 3: The second trophic level in a lake is-

(a) Phytoplankton

(b) Zooplankton

(c) Benthos

(d) Fishes

Zooplankton are primary consumers in aquatic food chains that feed upon phytoplankton. Therefore, they are present at the second trophic level in a lake.

Question 4: Secondary producers are

(a) Herbivores

(b) Producers

(c) Carnivores

(d) None of the above

Answer (d) None of the above

Plants are the only producers. Thus, they are called primary producers. There are no other producers in a food chain.

Question 5: What is the percentage of photosynthetically active radiation (PAR), in the incident solar radiation.

(a) 100%

(b) 50 %

(c) 1-5%

(d) 2-10%

Out of total incident solar radiation, about fifty percent of it forms photosynthetically active radiation or PAR.

Question 6: Distinguish between

(a) Grazing food chain and detritus food chain

(b) Production and decomposition

(c) Upright and inverted pyramid

(d) Food chain and Food web

(e) Litter and detritus

(f) Primary and secondary productivity