What is the difference between mechanical digestion and chemical digestion?

Apair of fruit flies reproduces and has 1,000 offspring. all 1,000 of the offspring have the alleles gg. what is the most likely combination of alleles for each parent

The fruit of a certain plant is sweet and fleshy. the seeds of this plant have a seed coat that is fairly tough. the seeds germinate better if they are exposed to acid, or scarification. what is the most likely type of dispersal for this seed? water animal wind

In "the man in the water," what was the remarkable occurrence that rosenblatt reported?