Assertion (A): In mammals, complex respiratory system has develop… - Vidyadip

MCQ

Assertion (A): In mammals, complex respiratory system has developed.
Reason (R): Mammalian skin is impermeable to gases.

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 the correct explanation of A.
C
A is true but R is false.
D
A is false but R is true.

✓

Answer

(b) Both A and R are true but R is not the correct explanation of A.
Explanation: Mammalian skin is impermeable so that water loss through it, is minimised. But mammals need far more oxygen to maintain their high metabolic rates than lower animals; so they need a more extensive respiratory surface. Thus a complex respiratory system has evolved in mammals to meet this need. The mammalian respiratory system consists of the nasal cavity, nasopharynx, larynx, trachea, bronchi, bronchiole and lungs.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Assertion & Reason" from MODEL PAPER 6→MODEL PAPER 6 — all question types→BIOLOGY STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

Assertion (A): Potassium is only essential for animals.
Reason (R): Along with sodium is essential for the conduction of impulses in nerve cells.

Assertion: Living organisms have more nitrogen and oxygen per unit mass than inanimate objects (e.g., earth crust).
Reason: Living organisms have more Ca, Mg, Na in them than inanimate object.

Assertion (A): Inspiration is initiated by the contraction of the diaphragm which increases the volume of the thoracic chamber in the antero-posterior axis.
Reason (R): The contraction of external intercostal muscles lifts up the ribs and the sternum causing an incn in the volume of the thoracic chamber in the dorso-ventral axis.

Assertion $(A):$ Receptors associated with the aortic arch and carotid artery also can recognize changes in $CO_2$ and $H$ concentration.
Reason $(R):$ It sends necessary signals to the rhythm centre for remedial actions.

Assertion (A): The mycelium is coenocytic in Zygomycetes.
Reason (R): The gametes are uninucleate.

Assertion (A): Excessive inflation of the lungs is prevented by the Hering-Breuer reflex.
Reason (R): On overstretching of the lungs, the stretch receptors send impulses along the vagus nerve to stimulate the expiratory centre.

Assertion (A): Inspiration occurs due to muscular relaxation.
Reason (R): During inspiration, the diaphragm and external intercostal muscle contract simultaneously

Assertion (A): Amylase enzyme stops its activity in stomach.
Reason (R): In stomach, pH is acidic due to presence of HCl.

Assertion (A): Proteins are a heteropolymer.
Reason (R): Dietary proteins are the source of non-essential amino acids.

Assertion (A): Abdominal muscle is related with respiration in animals.
Reason (R): Relaxation of abdominal muscles draws in air.