Easy
which of the following traits is totally determined by genes?
social skills
color of hair
intelligence
ability to sing

B. Color of hair

Height, hair color, and eye color,  are traits passed on by genes. The correct option is B. Genes are found inside the chromosomes which are enclosed in DNA molecules therefor, making B the correct answer. Genes carry all the information that are responsible for the traits and character found in living organisms. Genes are typically pass from the parents to the offsprings.

(hope this helps)

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.