If a scientist want to determine the are of the leaf what observation tool would he need

Hey me with this one❤❤❤❤ every organism needs food. does a cell also need it? explain very briefly.

The frequency of alleles in a population that is in hardy weinberg equilibrium? a . changes in each successive generation b. is less important than the frequency genotypes c. shows evidence of the process of natural selection d. remains the same over several generations

The variation among individuals, on which natural selection acts