Name the valve (sphincter) that controls food movement from the stomach into the duodenum.

Why are trees not found in the chaparral?

Calculate the capacitance of the nerve cell. how many unipositive charge carriers must cross the cell membrane to give the interior of the cell a potential of 0.1v?

What do prokaryotes and eukaryotes have in common

How are viruses and bacteria different?

These three regions are regions of net immigration:

Which of the following examples illustrates a pivot joint in use? A. you wind up to pitch a baseball B. you wave good bye to your friend C. you kick a football D. you look behind you

Bacterial cells have a much higher rate of metabolism than animal cells. Under ideal conditions some bacteria double in size and divide every 20 min, whereas most animal cells under rapid growth conditions require 24 hours.

What term includes all the biotic and abiotic elements in an area?

Best way to avoid infections and keep your immune system healthy

Certain fossils, such as Trilobites found after the Cambrian explosion, are found in the same geologic time period all over the world. What is the importance of fossils that are consistently found in the same geologic time period?