The haemoglobin content per 100 ml of blood of a normal healthy human adult is:

(1) 5 - 11 g

(2) 25 - 30 g

(3) 17 - 20 g

(4) 12 - 16 g

Assertion             :       Coughing and sneezing are necessary.

Reason                :      Coughing and sneezing are reflex actions.

Assertion   :       Most fish when out of water, die of suffocation.

Reason      :       Atmospheric air contains far less oxygen content than the dissolved oxygen in water.

Assertion       :       During inspiration, pressure of air falls in the thorax.

Reason          :       There is a rise in volume of thorax during inspiration.

Assertion      :       During inspiration, the volume of thorax increases.

Reason         :       This happens due to the relaxation of diaphragm and inspiratory muscles.

Assertion   :    Forceful expiration occurs through expiratory muscles.

Reason      :    Expiratory muscles expires quickly.

Assertion            :       Vital capacity is higher in athletes than non-athletes.

Reason              :       Vital capacity is about 3.5-4.5 litres in a normal adult person.

Assertion             :       Gill-lamellae in aquatic animals help in exchange of gases

Reason                :       Each gill lamella carries many blood capillaries.

Assertion          :      In mammals, complex respiratory system has developed.

Reason             :      Mammalian skin is impermeable to gases.

Assertion    :       Insects develop a complex system of air tubes called trachea for respiratory purpose.

Reason       :      Exchange through body surface is not possible in insects.