The correct answer is option B. Genotype AA, phenotype-Unaffected.
The cystic fibrosis is a condition caused by the inheritance of the two recessive allele, It is an autosomal recessive disease.
In the given case, the parents are carriers, and the carriers are always heterozygotes. Hence, the phenotype of the both parent should be Aa. A possible cross of the parents is shown in the figure below.
In case, the progeny have a single dominant trait, the child would not be affected, but will be a carrier and can pass the disease to offspring. In case, the child inherit both the dominant allele (homozygous dominant) from the parents, then he/she would be unaffected. In case, the phenotype of the child is homozygous recessive then it would be affected.
Peristalsis helps in storing food, breaking down food down and mixing it with juices secreted by stomach lining. Peristalsis in stomach helps in partial digestion of food called chyme.
Answer:
B. Layers that cut across the most other features are youngest.
Explanation:
Using the principles of cross-cutting relationships, you can determine the relative age of rocks found in the ground. The idea behind it is that the geologic feature which cuts another is the younger of the two features, and it had been around for 400 years. It's not very precise but it is good for determining relative age.