<h2>Answer </h2>
Neutral Variation
<u>Explanation</u>
Point mutations in noncoding regions of DNA result in neutral variation. The alleles which neither considerably sum to nor exceedingly lower from body consistency. It is the accumulation of such alleles located within a community that can be explained as expressing neutral variation. Neutral Variation implies in various alleles that are existing at an assigned genetic locus because those alleles are not distinct by natural selection.
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.
