4. in an emergency situation, a person with blood type a could receive
type a blood only.
o type o blood only.
o type a or type o blood.
o type a or type ab blood.

In an emergency situation, a person with blood type A could receive type A  or type O blood.

Explanation

Blood type A has anti-B antibody in the plasma and O type blood has no antigens. The presence or absence of antigens determine the blood group of individual. The O group is free of antigens and does not trigger an immune reaction in the body and hence are also known as universal donor.

The answer is (c.) esophagus, stomach, small intestine.
The entire sequence of the movement of food during digestion is: mouth, esophagus, stomach, small intestine, large intestine. Don't be tricked with answer (b.) mouth, esophagus, small intestine. After esophagus food moves through the stomach.