HELP ASAP What is a characteristic of all amphibians? are endothermic
lack a tail
covered in impermeable skin
have gills at some stage of development

Which of the following is not a characteristic of natural selection? 100 points pls more offspring are born than will survive to reproduce. mutations appear randomly breeding pairs are chosen by humans organisms that are better adapted are more likely to survive

Animal bodies (and even plant bodies for that matter) are complex enough that life couldn't exist without enzymes. enzymes are usually large, complex biological catalysts that are expensive to make. enzymes speed up the rate of chemical reactions without being used up during the reaction (they can be reused many times). they are highly specific in the reactions they regulate. knowing what enzymes are and how they function, why does this explain why complex life forms could not exist if there were no enzymes.

Amylase is an enzyme found in the human digestive system. why do you think it was important to keep the enzyme temperature above 37 degrees celsius (98.6 degrees f)? describe what might happen if the temperature decreased by 10 degrees celsius.