The correct answer is "A. carbon, hydrogen, oxygen and nitrogen".
Scientists believe that out of the 116 known elements, only 25 are used
by mammals (and therefore by humans). Out of the 25 elements that are
believed by scientists to support human life, only four of these
elements - carbon, oxygen, hydrogen, and nitrogen - make up about 96% of
the human body and are found in the basic structure of all biochemical
molecules within the human body. Because of this, carbon, hydrogen,
oxygen, and nitrogen are considered "the four essential elements"
supporting human life. However, it is also important to keep in mind
that although many of the other 25 elements present in the human body
are required in only small amounts, they play an important role in
keeping the body functioning correctly, as well.
I believe that the cells will decrease in size as water flows out of it. The red blood cell is hypotonic to the the solution while the solution is hypertonic, therefore, the blood cells losses water osmotically and decrease in size. Water moves from inside the cell to the outside by osmosis. The end result is the shrinking of the red blood cells.
All other organs, ducts, and glands in the reproductive system are considered secondary, or accessory, reproductive organs. These structures transport and sustain the gametes and nature the developing offspring.
Hope this helps!
<span>... beyond africa to asia and europe.</span>
<span>This would be fringing reefs. These reef systems grow near to the coastline as well as around islands and large continents. They are generally separated from the shore via shallow lagoons. They are the most common type of reef system on the planet. They are similar to Barrier reefs which also grow parallel to coastlines, but barrier systems are separated by deeper and much wider lagoons.</span>
