Oxygen rich blood returns from the lungs to the heart. Which 2 systems are most directly involved in this process. Respiratory and circulatory
Excretory and digestive
Circulatory and excretory
Digestive and respiratory

Biomass can be used to generate electricity. biomass relies heavily on agricultural crops. plants release carbon dioxide and water in combustion. plants use photosynthesis to originally generate the energy that is needed. the chemical energy of these plants all started with what energy source?

Abnormal softening of a gland is known as

Plz ! a scientist wants to produce a cow that makes a particular human protein in it’s milk the desired protein causes blood to clot and can be used to treat hemophilia (a blood clotting disorder). which of the following would be best for the scientist to use? a. genetic crosses. b. cloning. c. selective breeding. d. genetic engineering.