He is majoring in zoology at university.

Mammals can maintain a constant body temperature.

Animal experiments are necessary for the advancement of science, but there are also ethical issues.

He is learning about the handling of experimental animals.

Roundworms are an important part of the soil and contribute greatly to the health and fertility of the soil.

He is a world-renowned zoologist.

My pet is a dog.

In this situation, the proverb 'it is best to submit to circumstances' applies.

He drinks wine every day for his health, truly embodying the proverb 'good wine makes good blood'.

He always tries to make judgments based on the long run.