Insects comprise about what fraction of all animal species?

Insects comprise about what fraction of all animal species?

• A. Half
• B. A quarter
• C. Three quarters
• D. One tenth

Answer: (A)

Insects are the most species-rich group among animals, meaning they have the greatest number of different species. When scientists tally all described animal species, insects account for roughly half. That’s because there are about a million described insect species out of about two million described animal species overall. Their enormous variety comes from small size, short generation times, and the ability to occupy a huge range of habitats and ecological roles, often aided by metamorphosis that lets different life stages exploit different resources. So the option that matches this major pattern is about one half. The other fractions—one quarter, three quarters, or one tenth—don’t align with the actual proportion of described animal species that are insects.

Insects are the most species-rich group among animals, meaning they have the greatest number of different species. When scientists tally all described animal species, insects account for roughly half. That’s because there are about a million described insect species out of about two million described animal species overall. Their enormous variety comes from small size, short generation times, and the ability to occupy a huge range of habitats and ecological roles, often aided by metamorphosis that lets different life stages exploit different resources.

So the option that matches this major pattern is about one half. The other fractions—one quarter, three quarters, or one tenth—don’t align with the actual proportion of described animal species that are insects.