Answer:
If I am correct it is when the weaker individuals or mutated individuals are killed of by other predators or by nature. Because they cannot survive this is natural selection because they are killed of by nature. Then if they are weak their species will go extinct, thus they are naturally selected to die and only the strong species remain.
The answer's D. Cretaceous.
The ongoing active collision of the Indian and Eurasian continental plates challenges one hypothesis for plate motion which relies on subduction. ... The collision and associated decrease in the rate of plate movement are interpreted to mark the beginning of the rapid uplift of the Himalayas.
Answer:
false
Explanation:
i guess that is an endangered species but a threatened species is one whose habitats or survival is in danger mostly due to human factors like poaching and encroachment I guess
Answer:
Humoral immunity:
Humoral immunity is mediated by the macromolecules present in the extracellular fluid. This immunity provides protection against the pathogens present in the extracellular fluid. B- cells are mainly produced by the humoral immunity. The plasma cell and memory cells are generated in the human body. Antibodies kill the pathogens in humoral immunity.
Cell mediated immunity:
Cell mediated immunity is activated by the infected cells. This immunity provides protection against intracellular pathogens. T- cells are mainly produced by cell mediated immunity. T helper cells and T killer cells are mainly produced in the cell mediated immunity. Cytokines kill the pathogens in case of cell mediated immunity.