Answer:
3, Matter cannot be created or destroyed, only transformed
The red-green color blindness is a recessive X-linked trait. The females are not affected unless both the X chromosomes have the affected allele. Mostly, the females are the carriers, and the males are affected as they have only one X chromosome. In the given pedigree, the father of Irene have the normal allele, while her mother is a carrier. However, Irene is neither a carrier nor affected. This means that she carries normal alleles on both X chromosomes. Hence, her allele combination is
.
Answer:
I believe the answer is B
Homozygous.
You can tell in future that if both letters are either lowercase or upper case (e.g. TT or tt) the answer is always HOMOzygous. If the letters are different cases (e.g. Tt or tT) the answer is always HETROzygous. This is because 'homo' means 'same' and 'hetero' means 'different'.