Meiosis. Sexual recombination. Crossing over. Independent assortment. Mutations.
The two MAIN sources would be genetic(sexual) recombination and mutations. Mutations allow for genetic variation, while genetic recombination allows for genetic shuffling. :)
The bark of a tree is impervious to gases and water because bark cells are dead cells of the epidermis and compactly arranged without intercellular spaces. They contain a chemical called suberin in their walls that make them impervious to gases and water and it doesn't allow gases or water into the tree as bark cells are in the bark outer most layer of the tree.
Dissociate in water because water is a polar molecule
Climate change is the choice that answers your statement
This law states an organism has two different alleles for a trait and the allele that is expressed in the phenotype, masking the expression of the other allele,is said to be dominant. The allele whose expression is masked is said to be recessive.
