Q. Which of the following statements is/are correct?
1) Insects weigh as much as all the other species put together.
2) Insects are only useful for the environment in the presence of birds and other mammals.
3) Beetles are the largest group of all insects.
Select the correct answer using the codes given below

[A] 1 and 2 only

[B] 1 and 3 only

[C] 2 only

[D] All of the above

Answer: B
Notes:

Statement 1 is correct. nsects also outnumber all other species on Earth — of the million and a half-known organisms on the planet, over a million are insects. They weigh as much as all the other species put together — they are the majority of Earth’s biomass.

Statement 2 is incorrect. Insects are the principal denizens of Earth because of their key functions and they are the essential intermediaries between plants and all the vertebrates that depend on these. You could take away all the birds and mammals but Earth would still have productive crops as long as there are insects — they are the primary engineers of our planet.

Statement 3 is correct. Beetles are the largest group of all insects — about one of every four animals is a beetle as are around 30% of all insects