Answer:
B) Na+
Explanation: Na+ molecule is polar, oxygen and carbon dioxide are nonpolar molecules. The cell membrane is a <em>phospholipid bilayer</em> made up of lipid molecules with polar and nonpolar ends. Since it is a bilayer, two phospholipid layers are arranged, one on the other in such a way that one faces the back of the other. The non polar ends are away from outside and inside of the cell, while the polar ends faces towards all the molecules inside and outside the cell.
Since polar-polar molecules repel each other, Na+ can't pass through the cell membrane easily. So it uses the proteins attached the cell membrane inside and outside to transport such molecules by using energy in terms of ATP.
The answer you're looking for is C) hot & wet.
Arteries carry the oxygen-rich blood, veins carry the oxygen-poor ones
When the food reaches the small intestine .... it was absorbed by the villi present in it ! after absorption it reaches the blood where the food(glucose) mixes with plasma and reaches to different organ....there the food via capillaries and then via lymph reaches the cell and thus there further oxidation takes place.
so that was the path !!!
Answer:
It allows water and other molecules to enter and exit the system.
Explanation:
Plants have both a cell membrane and a cell wall. These allow needed molecules, such as water, to enter the cell. Both the cell wall and the cell membrane are semi permeable, which means that they choose what can enter and leave the cell. Molecules like water and other useful things to the cell enter it, and things such as waste leave the cell through the membrane and wall.
Remember that only plant cells have cell walls. Animal cells only have a cell membrane. But both the wall and membrane have the same purpose.
