What are the two examples of keratin and enzymes

Plzz hurry im being timed during times of vigorous physical activity, muscles require a constant supply of oxygen. how does the body respond to these needs? a. breathing rate and heart rate both decrease. b. breathing rate and heart rate both increase. c. heart rate decreases, but breathing rate remains stable. d. breathing rate increases, but heart rate remains stable.

The reactions that occur in the ribosome, where amino acids are combined to form proteins are anabolic or catabolic?

Describe the function of the endomembrane system? what organelles are involved?