Oxyhaemoglobin dissociates into oxygen and deoxyhaemoglobin at

1. low O₂, pressure in tissue

2. high O₂, pressure in tissue

3. equal O₂, pressure inside and outside tissue

4. all times irrespective of O₂, pressure

A person sitting at rest experiences a temporary cessation of breathing after forced deep breathing for a few minutes.This is due to:-

(1) too much CO₂ in the blood

(2) too much O₂ in the blood

(3) very little CO₂ in the blood

(4) both high O₂ and very little CO₂ in the blood

Epidermis is specialized for :-
(1) respiration

(2) absorption

(3) protection

(4) All of these
 

In the blood of an adult man the total content of haemoglobin is roughly

(1) several hundred grams

(2) tens of gram (10-100 g)

(3) several grams

(4) several hundred milligram

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.