What is known as a state of equilibrium, in which biological conditions (such as body temperature) are maintained at optimal levels?

The phylogenetic tree illustrates the relationship between humans and our closest living relatives. the tree was based on biochemical comparisons, including dna and amino acid sequences. according to the biomolecular data, we could infer that

In the diagram below, the northern hemisphere would be in what season at position a a.fall b. winter c.summer d.spring

Agene pool: a) is the collection of all the alleles found in a single species b) is the collection of all the alleles found in a single population c) is the collection of all the chromosomes found in a single population d) is the collection of genes in a species that allow the individuals to swim