The scientists studied as many as 1,130 ____ - from bacteria to primates - to understand how evolution built life forms that survived in the face of natural adversities.

Females have two X ___________. Males have one X and one Y.

_______ break down the food we eat so it can be converted into energy.

Bacteria can become _______ to antibiotics.

A groundbreaking new study suggests that the future of drug making might lie with _________ chickens whose eggs have been engineered to produce human proteins.

In "prevalent" where does the stress fall?

What does "keystone" mean?

In "parasite", the last syllable rhymes with SEAT or SIGHT?