The term' Peristalisis, which pumps blood towards the head in the open circulatory system of insects, also means 1. muscular conctractions that push food through the digestive system
2. air flowing into and out of the lungs
3. skeletal muscle contracting and relaxing to move a bone up and down

According to the theory of punctuated equilibrium, at what rate does speciation occur? species change depending on the rate of natural selection. after periods of stasis, new species evolve relatively rapidly. species change slowly and eventually form new species. some species change quickly and others change slowly to balance the overall rate.

What are some characteristics of a free enterprise economy?

Do you think the gene eef1 alpha1 supports cell theory? explain your response.