The scale scientists use to estimate the rate of change in proteins over time is called a a. protein meter
b. common estimator
c. chemical ruler
d. molecular clock

both male and female gametes are produced by meiosis of the germ cells. therefore, both male and female gametes are haploid. one male and one female gamete unite during the fertilization to form the diploid zygote. in seed bearing plants, pollen grain is the male gametophyte, which produces sperm cells.

it's not c. i took the quiz and got it wrong. so my best guess is b.

have a great day, and hope this .