Question

Muscles are arranged in pairs,
A. Enabling them to perform opposing movements.
B. Doubling their strength.
C. So they can take turns contracting and resting.
D. So if one is injured, the other can take over.

Answer 1

Hint:
Muscles are very specialized tissues that are mesodermal in origin. The muscles of our body constitute about 40-50% of our body weight. It has many special properties such as contraction, relaxation, excitability, and elasticity. Muscles have been classified on the basis of location, appearance, and nature of regulation. There are three types of muscles on the basis of location:- skeletal, visceral, and cardiac. On the basis of appearance, muscles can be striated or non-striated.

Complete answer:
Muscular movement is required to move our limbs, joints, jaws, tongue, etc. The contractile and relaxing property of the muscles helps in locomotion and other muscular movements of the body in almost all multicellular organisms. Perfect coordination is required between muscles and skeletal and neural systems for locomotion. Muscles always work in pairs. Muscles transfer the force to bones and cause movement by pulling them. This process is called muscular contraction. When one muscle of the pair contracts, it causes the bone to move in one direction whereas when the other muscle of the pair contracts it causes the movement in the opposite direction. The muscular pairs that work in such a manner are called antagonistic pairs. The muscle that contracts is called an agonist and the muscle that relaxes is called an antagonist.

Option ‘A’ is correct

Note:
In the human body, there are 650 muscles that work in a coordinated manner to cause movement. Almost every muscle represents one part of a pair of identical muscles. Thus, this results in around 350 muscle pairs in our body.