The molecular clock has been useful to determine the phylogenetic relationships of species based on the assumption that:

a species lineage accumulates genetic differences over time at a constant rate.

Explanation:

materials water oxygen those are the things i can think of in this moment.

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.