What is the difference between a homogeneous and a heterogeneous system ?

Secondary succession would most likely be taking place in a(n)

The negative change found inside the plasma membrane is created by potassium ions sodium ions hydrogen ions chlorine ions

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