Question

Paheli accidentally placed her hand over a flame and immediately
pulled it back. She felt the sensation of heat and reacted due to
the action of
(a) blood cells (c) nerve cells
(b) skin surface (d) nucleus of cells


NCERT Class VIII
Science - Exemplar Problems

Chapter 8. Cell - Structure and Functions

Answer 1

NERVE CELLS is the correct answer

Answer 2

Paheli felt the sensation of heat and reacted due to the response to stimulus by the nerve cells.

Answer - Nerve cells (Option B)

Explanation:

• When she places the finger into fire, the nerve endings in the finger upon receiving the heat stimulus sends it to the brain and spinal cord through the axons in a neural pathway.
• The brain or the spinal cord read this stimulus and recognizes as a pain stimulus and passes the reaction to the fingers.
• Pulling out the hand immediately is a reflex action here since the spinal cord immediately processes the signal even before it reaches the brain in order to prevent the finger from further damage due to heat.