Valves ensure blood flows toward your heart. Vein valves work to bring the blood that flowed down via arteries back up to your heart.
It has a huge roll and lol go learn bio
If someone pours salt water on a plant that is supposed to receive fresh water, the effects on the plant are swift and severe, beginning with the draining of existing water out of the plant cell.<span> Then, the cell membrane separates from the cell wall in a process known as plasmolysis. Ultimately, the plant shrivels up and no longer thrives</span>
<span>The trilobites seen in this image was once found widespread in the ocean. Something Changed To Limit and finally abolish their success. What do scientists use this example as proof of ? The answers are A. life changes over time and B. Vesitigial organisms once had a function in ancient times.The trilobites first appeared in the Cambrian period and though they entered a decline int the Devonian period, some of them survived until Permian time or for a period of 270 million years. They were divided into 3 segments and were early examples of arthropods. They tended to live on or near the bottom of the oceans and were scavengers in part and as well as living on the ocean floor some swam and fed on plankton. </span>