What was the variable in Redi's experiment?

meat sealed in jars that didn’t have contact with air

a swan neck flask that prevented air from getting in

uncovered meat that had contact with air

a straight neck flask to allow air to get in

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.

Drag the tiles to the correct boxes to complete the pairs. match the nitrogenous base of dna with its complement.

An organism's reproductive strategy includes all of the following except a. the number of offspring produced. b. the amount of energy expended in producing offspring. c. the length of time parental care is given d. the number of alleles an organism passes on.