What evolutionary change is linked to homologous structures?

Suppose you are estimating the size of a blue crab population. what is the population size if the number marked in the first catch is 40, the total number in the second catch is 200, and the number marked in the second catch is 50?

Identify the missing parts of the carbon cycle

Where is most of the fresh water on earth found a in the ocean b in glaciers and in ice caps c in rivers d in the soil