Answer:
a
Explanation:
If populations can interbreed, they are considered one species.
Enzymes are proteins and they control the speed of chemical reactions in your body. Without them, the reactions would happen too slowly to keep you alive.
Some break down larger molecules into smaller ones and those enzymes are in your stomach.
Answer:
Increase with a stimulant and decrease with a depressant
Explanation:
Stimulants and depressants are observed using various organisms. The way a stimulant works is by increasing the dopamine levels in the body. This in turn causes increased heart rate as would be seen in the chick embryo heart. On the other hand a depressant would lower dopamine levels. This would reduce the neurotransmitter and cause the heart rate to slow down.
