My biological clock is disrupted, and I've been having sleepless nights.

Invasive species can have a major impact on the natural environment.

We went to the zoo with our family on the weekend.

Vertebrates are organisms whose part of the skeleton is composed of a spine.

Wild animals are part of nature, and we should protect them.

She has zoophobia, and runs away as soon as she sees dogs or cats.

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

He is learning about the handling of experimental animals.

He is majoring in zoology at university.

Mammals can maintain a constant body temperature.