Spring (hydrology) and water supply network are subjects the hydrogeologist is concerned about; Water cycle, hydrosphere and water resources are larger concepts which hydrogeology is a part of; References
7.2 Photosynthesis occurs in chloroplasts in plant. cells. ï§ Chloroplasts are concentrated in the cells of the. mesophyll, the green tissue in the interior of the. leaf. ï§ Stomata are tiny pores in the leaf that allow. carbon dioxide to enter and oxygen to exit. ï§ Veins in the leaf deliver water absorbed by roots.
Oxygen is a Group 16 element. While about one fifth of the atmosphere is oxygen gas, the atmosphere of Mars contains only about 0.15% oxygen.Oxygen is the third most abundant element found in the sun, and it plays a part in the carbon-nitrogen cycle, one process responsible for stellar energy production.Oxygen in excited states is responsible for the bright red and yellow-green colours of the aurora.xygen is a Group 16 element. While about one fifth of the atmosphere is oxygen gas, the atmosphere of Mars contains only about 0.15% oxygen.