Answer:Darwin realized that existing heritable variation in a generation must be the starting point for a change in nature. In any generation, the animals in the litter are never quiet the same. And in the wild,such a tiny heritable variation might make all the difference between life and death.
Explanation:
I think the correct answer is the first option. The key features of chordates would be notochord, dorsal tubular nerve cord, pharyngeal pouches, and a tail. These features appears in some period of their lives. They are deutorostomes where the anus would be formed first before the mouth.
Cloning is a good idea because it replicates what we already have therefore genetically cloning something would lead to a better more functioning society.
Genetic engineering is a good idea as well because it creates a stronger DNA that is less likely to get diseases such as Diabetes and cancer. As well as it leads us to a more utopian society and could possibly eliminate the need for breeding.
Answer:
The first heart sound (S1) represents closure of the atrioventricular (mitral and tricuspid) valves as the ventricular pressures exceed atrial pressures at the beginning of systole (point a). S1 is normally a single sound because mitral and tricuspid valve closure occurs almost simultaneously.
Explanation:
