Cellular respiration and photosynthesis are important parts of the carbon cycle. The carbon cycle is the pathways through which carbon is recycled in the biosphere. While cellular respiration releases carbon dioxide into the environment, photosynthesis pulls carbon dioxide out of the atmosphere.
D. They make their own food using energy from the sun. Trees use a process called photosynthesis to convert light energy from the sun, carbon dioxide, and water into glucose (the food) and oxygen.
The answer is; Sodium (Na+) and Potassium (K+) Ions
These cations are pumped out of the cell by Na+-K+ transmembrane protein pumps leaving the inside of the cell electronegative in relation to the extracellular matrix. This membrane potential is significant especially for neurons. Depolarization of the membrane enables transmissions of an impulse along the neurons.
I would go with endoplasmic reticulum.