NO LINKS Explain how a knee-j erk reflex occurs.

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

What is a gene ? a) a section of a protein that codes for dna. b) the alternate version of a trait. c) the visible trait in the f1 generation. d) a section of dna that codes for a specific trait .

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.