Francine is developing a model of the carbon cycle, which involves the movement of carbon among various Earth systems. She begins by drawing the diagram shown below. Her friend Byron evaluates the model and suggests that she thicken the arrow leading from fossil fuels to the atmosphere. His reasoning is that fossil fuels are being burned at a much faster rate than natural processes are restoring them.

Label the model to show where it represents photosynthesis, cellular respiration, and the burning of carbon-containing materials.

The answer would be c, white eyes are homozygous recessive. in the early 1900s, morgan conducted several experiments with vinegar  flies (drosophila). one  sample revealed an anomaly: a  white-eyed, single male fly. he attempted to breed this fly with the typical red-eyed females. the offspring were all red-eyed. using flies from this new generation (brother-sister pairs)  produced some red-eyed and a few white-eyed flies. the white-eyed were all male. in later experiments, he was able to produce white-eyed females. this proved that white eyes are not lethal to either sex (ruling out a and b). since the percentage of white eyes to red eyes is so low, white eyes are not a dominant trait. it would be a recessive trait. 

Im not sure if you still need this but the answer is 300 hz450 hz  i just did this lesson so , wish you the best of luck and take care