What did the common ancestor of all modern tetrapods look like 350 million years ago?

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?

Iwill give brainiest to first person who gets it ! what are 3 basic types of interactions we see in an ecosystem?

Crossing over and independent assortment are important activities that occur during meiosis. what is the significance of these activities