1.
Option D
2.
Option B
3.
The three main parts of nerve cells are dendrite, cell body and axon. Dendrite: It detect information and conducts the messages towards the cell body.
Cell body: It contains nucleus, mitochondria, and other cell organelles. It maintains the growth of the cell.
Axon: It conducts messages away from the cell body and pass to the next neuron.
4.
Reflex actions are sudden responses. It is involuntary action which does not involve thinking. e.g.. Pricking of pin is the stimulus. Sensory nerve cell carry this message. Further in spinal cord, relay neuron transmit the signal. On receipt of signal, motor neuron draws back the hand.
5.
Option A
6.
The wall of esophagus relaxes and contracts which helps the food to push towards stomach.
7.
Option B
8.
Axial skeleton and the Appendicular skeleton.
9.
Option C
10.
Option B
11.
Option A
12.
Option B
Solution:
Cartilage is found within all movable joints.
13.
Cardiac muscles cause the heart to pump the blood throughout the body. They work nonstop for entire life.
14.
Option B
15.
Bones are composed of calcium, phosphorus, and a fibrous substance known as collagen.
16.
Tibia and fibula are the two bones of lower leg.
17.
1. Voluntary muscles are consciously controlled. Involuntary muscles can not be controlled, as they work on their own. 2. Voluntary muscles are found almost allover the human body whereas involuntary muscles are only found in heart. 3. e.g. actions such as reading, writing, walking or running, use voluntary muscles. Involuntary muscles are involved in pumping blood throughout the body.
18.
The muscles which work on their own without our control are called as Involuntary muscles. e.g.. movement of inner part of body such as stomach, intestine.
19.
Option D
20.
Option A
