It is essential for heart muscle cells to beat in a coordinated fashion. the cell junctions that would best facilitate this are

Why should the united state be concerned about air pollution in china?

List two limitations of natural selection

The earth consists of a variety of different organisms. despite their diversity, however, some similarities on the structural and metabolic levels may be seen. these similarities can be attributed to a. similarities among organisms in their proteins and nucleic acids. b. the ability of organisms to readily adapt to sudden environmental changes. c. similarities in organisms' habitats and niches. d. the ability of all organisms to interbreed and produce new species.