The slightest change in pH can destroy the substance or organism. The pH of a cell's interior helps regulate the cell's chemical reactions. For example, the pH of blood is 7.4, if blood falls to 6.8 or lower or 8.2 or higher, it results in death.
Answer:
Option D, Gastric Juices
Explanation:
The second line of defense is a non specific defense mechanism in which no specific individual is targeted but all invaders are killed in general way. Some common mode of second line of defense are - Phagocytic cells (white blood cells), inflammatory responses, macrophage system etc. The second line of defense comes into action when the invader has surpassed the first line of defense which include either physical barrier like skin, mucous membrane, hair, cilia etc. or chemical barriers like gastric juices, saliva, Hyaluronic acid etc.
Hence, gastric juice does not belong to second line of defense.
Thus, option D is correct.
<span>as animals get separated from each other, they soon start to adapt to the new environments which is called speciation</span>
Meiosis - the cells divide to produce 4 haploid cells
