A shell is considered as biotic (living) because it is a hard, rigid covering of many animals such as snail, sepia, pila, turtles, sea urchins. A shell is protective outer layer of these soft bodied animals.
Might just be D must of them don't seem right to me
A, i think, hope this helps:)
The correct answer is option D, Temporal isolation
Temporal isolation is the mechanism which prevents the mating of closely related species living in the same ecosystem. Basically the reproductive barriers prevent these species from interbreeding. Temporal isolation is a prezygotic barrier that causes “time isolation” between the breeding period of two closely related species. The difference in time could be “difference in time of day”, “ difference in season of mating”, “difference in months” and in some cases “ difference in years”.
Answer:
Explanation:
Immunity to a disease is achieved through the presence of antibodies to that disease in a person's system. Antibodies are proteins produced by the body to neutralize or destroy toxins or disease-carrying organisms. Antibodies are disease-specific. Viruses make us sick by killing cells or disrupting cell function. Our bodies often respond with fever (heat inactivates many viruses), the secretion of a chemical called interferon (which blocks viruses from reproducing), or by marshaling the immune system's antibodies and other cells to target the invader. A vaccine works by training the immune system to recognize and combat pathogens, either viruses or bacteria. To do this, certain molecules from the pathogen must be introduced into the body to trigger an immune response.
These molecules are called antigens, and they are present on all viruses and bacteria.
