While performing an autopsy, Jina finds an insect's egg in the victim's ear. Which scientific field will Jina use to determine which type of insect's egg it is?

Entomology.

Explanation:

Entomology is the area of zoology that studies insects in all their life stages. Entomology is responsible for studying the physical, behavioral and reproductive characteristics of insects. It also studies the relationships between insects and other beings, including humans. It is a very important area of study, as it develops knowledge used, for example, in agriculture and human health.

As Jina found an insect egg in the ear of the body she was performing an autopsy on, she must resort to entomology studies to be able to find out which species of insect the egg belongs to.

I think it would be entomology considering it is the study of insects.