According to sigmund freud, which part of the mind is composed of biological drives and consequently is the source of psychic energy

The Id.

Explanation:

According to Freud, Id is the part of the mind that is composed of biological impulses that contains our basic psychic energy, or libido, and is expressed through stress reduction. Thus we act in an attempt to reduce this tension to a more tolerable level. To meet the needs and maintain a comfortable level of tension, it is necessary to interact with the real world. For example, hungry people should go in search of food if they want to release hunger-induced tension. Therefore, it is necessary to establish some sort of proper link between the demands of id and reality.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.

b is dominant over the allele for the white fur.