Question

a leech attaches to an animal and feeds off the animals blood. what happens to the animal the leech attaches to in this scenario? it loses nutrients to the leech. it gains nutrients from the leech. it will be killed and eaten by the leech. it will kill and eat the leech.

Explanation:

Leeches are parasites. Parasites live on or in a host organism and obtain nutrients from the host. In this case, the leech (parasite) attaches to the animal (host) and feeds on its blood. Blood contains nutrients. So the animal loses nutrients to the leech. The leech does not provide nutrients to the animal (so "It gains nutrients from the leech" is wrong). Leeches usually do not kill and eat the host (so "It will be killed and eaten by the leech" is wrong). The animal in this scenario is the one being fed upon, not the one attacking (so "It will kill and eat the leech" is wrong).

Answer:

It loses nutrients to the leech.