English Medium कक्षा १० - CBSE Question Bank Solutions for Science

What will be the amount of energy available to the organisms of the 2nd trophic level of a food chain if the energy available at the first trophic level is 10,000 joules?

Write the number of covalent bonds in the molecule of butane, C₄H₁₀.

Which of the following are always at the second tropic level of food chains?

State with reason any two possible consequences of elimination of decomposers from the Earth.

"Energy flow in a food chain is unidirectional" Justify this statement.

In a food chain of frog, grass, insect and snake, assign trophic level to frog.

What are covalent compounds?

Why covalent compounds are different from ionic compounds?

List three characteristic properties of covalent compounds.

Give reason to justify the following: The existence of decomposers is essential in a biosphere.

Give reason to justify the following: Flow of energy in a food chain is unidirectional.

List two biotic components of a biosphere.

Why are green plants called producers?

The first trophic level in a food chain is always a green plant. Why ?

List two main components of ecosystem?

We do not clean natural ponds or lakes but an aquarium needs to be cleaned regularly. Why is it so ? Explain.

Explain why carbon forms compounds mainly by covalent bond.

List two important roles play in the environment by decomposers.

Elements forming ionic compounds attain noble gas configuration by either gaining or losing electrons from their outermost shells. Give reason to explain why carbon cannot attain noble gas configuration in this manner to form its compounds.

Name the type of bonds formed in ionic compounds and in the compounds formed by carbon.