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.
species
15
Females have two X ___________. Males have one X and one Y.
chromossomes
15
A groundbreaking new study suggests that the future of drug making might lie with _________ chickens whose eggs have been engineered to produce human proteins.
genetically modified
15
In "parasite", the last syllable rhymes with SEAT or SIGHT?
sight
15
Bacteria can become _______ to antibiotics.
resistant
15
What does "keystone" mean?
something that is very important
20
_______ break down the food we eat so it can be converted into energy.