Answer:
Autorhythmicity of the heart
Explanation:
It is the study of the characteristics features of the cardiac muscle cells with the ability to initiate action potential at certain level without connection to any external stimulus which the heart beats constantly and rhythmically. Cardiac muscle cells controls the rate of contraction of heartbeats.
I think it’s phenotype bc phenotypes is what the natural selection acts on bc it’s what interacts with an organisms environment and not the genotype.
Lipids are fat's so they are energy more than carbohydrates
