On what continent would you find 20°n 20°e?

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.

the tricuspid valve is present between right atrium and right ventricle

the answer is c. it will give up it's valence electron to the other atom.