How does the vestigial thumb a frog?

Which macromolecule catalyzes chemical reactions this be considered enzyme chemical reactions thus he considering enzymes

Why are current extinctions of concern to enviromentalists?

Why are carbon dioxide concentrations expected to increase? a carbon dioxide concentrations are expected to increase, because fossil fuel burning is expected to increase b. carbon dioxide concentrations are expected to increase, because of an increase in agriculture. c. carbon dioxide concentrations are expected to increase, because more land will have to be cleared for increasing populations and agricultural use. d. all of the above select the best answer from the choices provided mark this and return save and exit next submit submit