Assertion             :       Aerobic respiration involves the exchange of respiratory gases twice.

Reason                :       Exchange occurs from lung to heart and then heart to lung.

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

Assertion             :       In mollusca, circulatory system is of closed type.

Reason               :       The blood of mollusca contains haemoglobin

Assertion  :       Histamine is involved in allergic and inflammatory reactions.

Reason     :       Histamine is a vasodilator

Given below are two statements: 

Which of the following is true about respiration
1. it is for energy liberation

2. it can occur both O2 presence and its absence

3. In humans R.B.C show anaerobic respiration

4. All of these

How many of the following invertebrates exchange O₂ with CO₂ by simple diffusion
(Sponges, Coelenterates, flatworms, Annelida, Arthropoda, Mollusca, Pisces,)
1. 6
2. 5
3. 4
4. 3

Frogs respire through
1. Skin
2. lungs
3. buccal cavity
4. All of these

Respiratory organ of scorpion is
(1)Book-lungs

(2)Book-gills

(3)Buccal cavity

(4)Lungs

Which of the following is true
1. Gills are used by most of the aquatic animals

2. lungs are used by most of the terrestrial animals

3. Mammals have a well developed respiratory system

4. All of the above