D. The nervous system produces gametes
From the principle of mass conservation in a chemical process, the total mass of the reactants should be the same as the total mass of the products. So, the best answer here would be the first statement.
This is entirely theoretical as photosynthesis is neither a completely efficient process nor does it take place in an isolated system.
The second statement is incorrect since the products of photosynthesis are glucose and oxygen gas, which are completely different compounds from the water and carbon dioxide reactants.
The third statement is incorrect not only because it contradicts the principle of mass conservation, but because—if anything—mass is lost in the course of an inefficient chemical process like photosynthesis in the form of energy wasted as heat.
The last statement is incorrect for the same reason as the second statement is incorrect; the products are completely different substances from the reactants. For example, one of the products—glucose—can undergo combustion. One of the reactants, water, cannot combust.
Disruptive selection favors individuals at both extremes of variation.
Disruptive, also known as diversifying selection, has to do with choosing phenotypes which are really different, but have their own advantages and possibly disadvantages. It is a way of selecting which organism is going to survive, and which isn't.
Prokaryotic and Eukaryotic Cells.
Prokaryotic cells are the simplest (arguably) cells, in being that they have many less organelles inside.
Prokaryotic cells have a cell membrane, DNA, ribosomes, and a few other things.
Eukaryotic cells, on the other hand, are much more complex. They have many organelles, such as the endoplasmic reticulum, vacuoles, the golgi apparatus, and others.
Metabolic asphyxiation is the situation where a person's body has become severely deprived of oxygen, this can arise from carbon monoxide poisoning, drowning, drug overdose, hanging, respiratory diseases, sleep apnea, prolonged exposure to chlorine gas, strangling, seizure amongst other causes. With a deprived oxygen supply, a patient can experience severe brain or organ damage, as the cells are starved of the oxygen, the body will suffer and if left untreated, will result in the patient's death.
