Which of the following is a true statement? A Periods form horizontal rows; groups form vertical columns
B Groups form horizontal rows; periods form vertical columns
C Categories form horizontal rows; gases form vertical columns
D Gases form horizontal rows; categories form vertical columns

•there must be variation for the particular trait within a population.

•the variation must be inheritable (that is, it must be capable of being passed on from the parents to their offspring).

•individuals with one version of the trait must produce more offspring than those with a different version of the trait.good

explanation:

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the answer is c. altitude. hope this ! #brainiac