What measures the amount of displacement in a longitudinal wave

Which of these serves as a reference for comparison during a scientific investigation? a)outcome variable (dependent variable) b) test variable (independent variable) c)control group d)hypothesis

Dermal tissue in plants stores 1.extra food 2.transports water and nutrients 3.transports waste materials 4.is similar to epithelial cells in animals

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