He learned about the concept of 'class' in biology class.

I saw a globe skimmer in the park.

He was running while holding a bag.

He always carries an umbrella around.

He was holding my hand tightly.

He told me the whole story of the incident.

He is world-famous as an entomologist.

Insects are an important part of the natural world.

He is an expert in entomology, especially knowledgeable about butterflies.

This insect belongs to the subfamily of stink bugs.