An eye consisting of an array of numerous small visual units, as found in insects and crustaceans.
ANSWER:
Problem faced include; habitat loss and degradation, disease outbreak, invasive species, pollution, over‐exploitation/overfishing, climate change etc.
EXPLANATION:
Problem:
Habitat loss and degradation, disease outbreak, invasive species, pollution, over‐exploitation/overfishing, and climate change are notable problems experienced by freshwater and marine fishes.
Solution:
Anthropogenic activities and stressors that rapidly threaten freshwater and marine fishes are curbed through legislation and other means to prevent extinction of fishes.
Through conservation programs that plans for individual species to more species of entire faunas of a particular location also boost population size and prevent hunting of threatened or endangered species in both realms.
Overtime, genetically modified fishes which can develop resistance to diseases are introduced to the realm.
Moreso, waste channels through which pollutants gets into the water bodies are well-treated for safety of fishes.
Cloning is a process of producing genetically identical organisms through the techniques of biotechnology. Reproductive cloning of animals involves the somatic cell nuclear transfer in which the nucleus from an adult donor cell is transferred to an egg cell from which the nucleus has been removed. It is then incorporated into the uterus of a surrogate animal.
Pet cloning is not acceptable because of the following reasons-
(1) Its a very expensive procces with a high rate of failure.
(2) The clones produced tend to develop health problems. Large Offspring Syndrome (LOS) with very large organs is observed showing problems with blood flow and breathing with respect to heart and lungs, renal failure and other complicated issues.
(3) The clones are susceptible to skeletal abnormalities, higher rates of infection and tumour development. This results in a high mortality (death) rates.
(4) Since a surrogate mother is involved in the process of cloning, they experience a lot of health problems while carrying the embryos and sometimes it can be even killed.
Thus, cloning of pets is not acceptable as it affects both the cloned animal and the surrogate mother which is not preferred. Instead, adopting a homeless pet will provide shelter to another animal with a better nourishment.
<span>The formation of the fertilization envelope (slow-block to polyspermy) requires an increase in the availability of </span>calcium ions.
Slow-block to polyspermy is also called cortical reaction. In this reaction, the sperm will be permanently blocked by cortical granules. The release of calcium ion will trigger this reaction.
I think the correct answer from the choices listed above is option B. During diffusion, when the concentration of molecules on both sides of a membrane is the same, the molecules will <span>stop moving across the membrane. This is because equilibrium has already been achieved and there is no more driving force which is the concentration gradient present.</span>
