Abrown dog is crossed with two different black dogs. the first cross produced only black dogs and the second cross produces equal numbers of black and brown dogs. what is the genotype of the brown dog? the first black dog? the second black dog?

humans, along with other animals and plants, have linear chromosomes that are arranged in pairs within the nucleus of the cell. the only human cells that do not contain pairs of chromosomes are reproductive cells, or gametes, which carry just one copy of each chromosome.

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.