Which type of water is the most dense?
a. cold water with low salt content
b. cold water with high salt content
c. warm water with no salt
d. warm, salty water

Consider the diagram below, which represents components of the biosphere. what do the two arrows in the diagram most likely represent? a. radiation b. photosynthesis c. cellular respiration d. energy conversions will give to anyone who answers quickly

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.

Which of the following is one of the four conditions necessary for natural selection to occur in a population? fewer organisms are born than the habitat can support mutation does not occur organisms have identical characteristics variation is inherited