Why do organisms at the lower level struggle less that organisms above them?

Sammi is studying the interaction of the digestive and circulatory systems in the human body. she has listed various processes that occur in each of the systems. put the processes in order to describe the interaction between these two systems. tiles nutrients diffuse through the villi of the small intestine. digestive processes break nutrients down in the mouth, stomach, and small intestine. blood is pumped through the circulatory system to deliver nutrients to other organs. nutrients are ingested at the mouth. nutrients enter the capillaries of the circulatory system. sequence

The use of dna as evidence in criminal investigations became possible because of the

Amale bird-of-paradise uses a dance to attract mates in which it flaps its tail feathers on the ground and jumps around a potential female mate. a different male bird-of-paradise does a similar dance but it jumps around the female in the opposite direction. the female bird is only attracted to one style of dance, in one direction. this is an example of speciation.