Question

Stimulus : A detectable change in the internal or external environment.
Response : Any behaviour of a living organism that results from an external or internal
stimulus.
Read the following statements and conclude which statement is not an example of response
to stimulus.

a) Salivating when we see delicious food items.
b) Mimosa plant closing its leaves when we touch it.
c) Closing of eyes when light falls.
d) A chick hatching out of an egg.

Answer 1

Answer:

All organisms, from primitive prokayotes to most advanced and complex eukaryotes, are able to sense and respond to environmental factors. The stimuli are perceived by sense organs in higher animals through sensory receptors e.g., eyes, ears, nose. Plants do not possess such sense organs. However, they do respond to external factors such as light, water, temperature, pollutants, other organisms, etc. Human beings have an additional facility of self consciousness (awareness of self). Consciousness and response to stimuli are said to be the defining properties of living organisms.