What is meant by stimulus and reaction?
Stimulus is the change in the environment or environmental factors to to which the organism can respond or react. Theresponse shown by organisms towards or awaya stimulus is called reaction.
What are hormones? Write down their properties and functions.
Hormone are the chemical messengers which control, co-ordinate and integrate the function of various organs of the body.
Its properties are:
- It is produced by endocrine glands.
- They are required in small amount and their effect are long lasting.
- They are chemically proteins, steriod and amino acid.
- They act as chemical messengers.
Its functions are:
- It stimulate and control various psychological and metabolic.
- They regulate growth and reproduction.
- They synthesize, store and utilize various substances.
- They conserve water and minerals in the body.