To replace fossil fuels, the world must find a way of producing fuel from renewable energy. one of the most promising fuels of the future is hydrogen, which could potentially be produced in algae using the power of sunlight. green algae contain enzymes (hydrogenases) that can convert hydrogen ions (h+) and electrons to hydrogen gas (h2). the hydrogen ions used by the hydrogenase come from

a- atp synthase.

b- water.

c- organic sugars.

d- atp.

e- rubisco.

hypoxemia refers to a below usual concentration of oxygen in the blood, mainly in the arteries. hypoxemia is an indication of an issue associated with circulation or breathing and may lead to various symptoms like shortness of breath.  

the condition is identified by determining the level of oxygen in the blood sample obtained from an artery. it can also be predicted by determining the oxygen saturation of the blood with the application of a pulse oximeter.  

the normal arterial oxygen is about 75 to 100 mm hg. the values underneath 60 mm hg is generally considered with the requirement for supplemental oxygen. the normal pulse oximeter readings generally range between 95 to 100 percent. the values under 90 percent are regarded as low.  

in the given case, the oxygen saturation is measured at 93 percent, hence, there is no need to administer oxygen, that is, one should withhold oxygen.  

imagine a line passing through the center of earth that goes through both the north pole and the south pole. this imaginary line is called an axis. earth spins around its axis, just as a top spins around its spindle. this spinning movement is called earth's rotation. at the same time that the earth spins on its axis, it also orbits, or revolves around the sun. this movement is called revolution.

your answer is going to be physical weathering