During exercise stroke volume increases because more blood is sent back to the heart due to the muscles squeezing blood in the veins
The correct substitutes would be " A. Ellos lo compraron
In English, Ellos compraron El Reloj Pulsera means : They (masculine) bought the watch
Reloj : Masculine singular Pronoun, which means that the objective pronoun should be : LO
Hope this helps
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.
It can't be released by photosynthesis
