I think B but I maybe wrong please correct
Sex cells will always contain half of the number of chromosomes needed for a being. So if a fishes sperm cell contains 12 chromosomes and the ovum also contains 12 chromosomes then when fused together they will have 24 chromosomes in total.
In order for the process of the fish to even be made the sperm and ovum must be fused together. Therefore the number of chromosomes that would be found in the cells forming the gills is 24 chromosomes.
Answer: overpopulation of predators
Explanation: Overpopulation of predators is the correct option. Predators are the organisms which kill other organism so as to obtain them as food. The organism being killed is called as the prey.
If the population of the predators increase this will lead to the extinction of many species of prey. As it is evident that every organism in the ecosystem has a typical role to play. Therefore, it can be said that role of prey will not be performed and this may lead to disturbance in the ecological balance.
I believe that last one is true (photosynthesis of plants)
good luck
