A person is mentally sick if one is
Worried
With moods fluctuating between depression and elation
Excessively happy
Extra talkative
The harmful allele of sickle cell anemia has not been eliminated from human population. Such afflicted people derive some other benefit. Discuss.
The caustative organism of $AIDS$ spreads by
The vector for causing sleeping sickness in man is
Antivenom against snake poison contains
$A$ - Acid in the stomach and saliva in the mouthare examples of physiological barrier.
$R$ - Tears from eyes is example of physicalbarrier.