How do rivers become larger as they travel across land?
1. Groundwater rises, adding water to rivers.
2. Tributaries combine, adding water to rivers.
3. Ice sheets melt slowly, adding water to rivers.
4. Rainfall in an area increases, adding water to rivers.

Use the drop-down menu to match the following definitions to the corresponding terms. the total variety of organisms that live in the biosphere a group of organisms that breed and produce offspring that can breed all of the biotic and abiotic factors in an area

What was the land like over 500 million years ago? what was under the sea?

How are mutations continually being generated in a population (what are some of the causes of mutatuions? ) explain