Question

Column I lists the components of body defense and column II lists the corresponding descriptions. Match the two columns.

Column I	Column II
A. Active natural immunity	p. Injection of gamma globulins
B. First line of defense	q. Complement proteins and interferons
C. Passive natural immunity	r. Direct contact with the pathogen that have entered inside
D. Second line of defense	s. Surface barriers
	t. Antibodies transferred through the placenta

• A. A- s, B- r, C- t, D- q
• B. A- r, B- s, C- q, D- t
• C. A- r, B- s, C- t, D- q
• D. A- t, B- r, C- q, D- p

Answer 1

Answer: (C)

A- r, B- s, C- t, D- q

During infection and diseases, human body faces a battle against invaders such as bacteria, fungi, parasites, and viruses as well as nonliving toxins, chemicals, and drugs. Nevertheless, the human body is equipped with natural defense systems to fight off these invading microbes.

While, the skin and mucous membranes of the organs are the first line of defense that acts as a physical surface barriers preventing penetration by microbes or destroying the bacteria, the active natural immunity directly acts on the pathogens that have entered inside.

The second line of defense is the complement system made up of a group of proteins that float freely in the blood and combine with antigens to destroy microorganisms.

Passive natural immunity refers to instances when the human body receives the antibodies from another individual or source - the first is when the antibodies are transferred from the mother to the offspring through the placenta.

Therefore, the correct answer is option C.