196: Hormones which are necessary for the development of the human body are secreted by:
(a) Thyroid gland
(b) Pituitary gland
(c) Parathyroid gland
(d) Exocrine gland
197: Assertion (A) :
The temperature of a metal wire rises when an electric current is passed through it.
Reason (R):
Collision of metal atoms with each other releases heat energy.
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, but R is NOT a correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Explanation:
When electric current passes through the wire the temperature of the metal wire rises because by getting energy the metal atoms collide with each other which releases energy.
198: Most of the desert plants bloom during night time because
(a) their blooming is controlled by low temperature
(b) they are sensitive to the phases of moon
(c) the desert insects eat away flowers during day time
(d) the desert insects are active during night time
Explanation:
Most of the desert plants bloom during time because, the desert insects are active during night time which helps in pollination.
199: German silver is an alloy of
(a) copper, zinc and nickel
(b) copper, iron and tin
(c) iron, chromium and nickel
(d) copper, aluminium and nickel
200: The ductless and secretory glands in the human body are known as:
(a) Endocrine glands
(b) Exocrine glands
(c) Salivary glands
(d) None of the above