Which of the following is an example of an organ? heart
respiratory system
tissue
muscle cell

Amylase is an enzyme found in the human digestive system. why do you think it was important to keep the enzyme temperature above 37 degrees celsius (98.6 degrees f)? describe what might happen if the temperature decreased by 10 degrees celsius.

Acommon kind of mechanical weathering is called

There are fewer than 100 naturally occurring elements in the universe, but there are millions of different unified substances. explain how this can be true.