How is a personal watercraft (pwc) propelled through the water?

In humans, the small intestine can be over 8 meters (26 feet) long. Why is the organ so long

Hinge joints are capable of only which two movements?

Animals obtain energy through a series of chemical reactions in with sugar and oxygen gas are reactants this process produces water and carbon dioxide as waste products how might you use a radioactive isotope to find out whether the oxygen in CO2

If the concentration of solutes (salts, sugars, ions) in the blood rises above a certain level then what happens in the kidney tubules?

Into what structure does the embryo excrete waste?

What is the genotype for individual D

Are aliens and UFO's real

What happens once intercelluar signals reach the inside of a cell using some type of receptor? the signal stops. the signal is transferred to the cytoplasm. the signal produces protein. intracelluar communaction takes over.

What is extinction and why does it occur?

Corn smut and wheat rust are crop diseases caused by fungi.