Cystic fibrosis is an inherited disease that occurs when an individual is homozygous for a recessive allele. if parents are both heterozygous for this characteristic, what is the probability that their first child will have cystic fibrosis?

25%

Extra information:

Heterozygous means that the individual posesses two different alleles for a particular trait. Homogenous means that the individual posesses two similar alleles.Both parents are heterogeneous, which means that they have a recessive and a dominant allele. If you make a scheme, like the following:
A a
A AA Aa
a aA aa

you can calculate that the chances of the child (doesn't matter whether it is the first or not) has a chance of 25% to have two recessive (aa) alleles and therefore have Cystic Fibrosis.

The correct answer is letter C, Archaic Homo Sapiens occur only in parts of Europe and Asia. These species are an early form of the Homo sapiens that are anatomically distinct from modern humans. These neanderthals can be found in Europe, and are classified as Solo Man in Asia all belonging to archaic humans.