I can’t answer how lichens arrive in a barren landscape but I can answer the 2nd part
Lichens grow when exposed to water. When wet, lichens begin to photosynthesize.
Amino Group, Carboxyl Group, and the R group
Answer:
The autosomal trait are present on the autosomes and does not have any influence on the sex of the organism. Two main types of autosomal trait are autosomal dominant and autosomal recessive trait.
a. The trait discussed in the question must be the autosomal dominant trait. As the normal and affected children are produced by the affected parents cross. The appearance of the normal child determines that the trait is dominant.
b. Since both the parent are affected but the normal child has been produced from the cross. The parents must be heterozygotes for the trait, (Aa). Their cross will produce the progeny AA, Aa and Aa (affected) and aa (normal).
