The most plausible hypothesis to explain why species richness is higher in tropical than in temperate regions is that a) tropical communities are younger. b) tropical regions have more available water and higher levels of solar radiation. c) warmer temperatures cause more rapid speciation. d) biodiversity increases as evapotranspiration decreases. e) tropical regions have very high rates of immigration and very low rates of extinction

You have just sequenced a new protein found in mice and observe that sulfur-containing cysteine residues occur at regular intervals. what is the significance of this finding? it will be important to include cysteine in the diet of the mice. cysteine residues are required for the formation of α helices and β pleated sheets. cysteine residues are involved in disulfide bridges that form tertiary structure. cysteine causes bends, or angles, to occur in the tertiary structure of proteins.