Assertion : Mast cells help in body defence.
Reason : Mast cells phagocytose & destroy microbes.
Assertion : Surface of skin is impervious to water.
Reason : Surface of skin is covered by stratified cuboidal epithelium.
Assertion : Bones possess longitudinal canals called lacunae.
Reason : Lacunae carry blood vessels & nerves to the bones.
Assertion : Cartilage (protein matrix) and bone (calcium matrix) are rigid connective tissue.
Reason : Blood is connective tissue in which plasma is the matrix.
Assertion : Specialization of cells is advantageous for the organism.
Reason : It increase the operational efficiency of an organism.
Assertion : Histamine is related with allergic and inflammatory reactions.
Reason : Histamine is a vasodilator.
Assertion : Mast cells in the human body release excessive amounts of inflammatory chemicals which cause allergic reactions.
Reason : Allergens in the environment on reaching human body stimulate mast cells in certain individuals.
In water, frogs respire through
(A)Skin
(B)lungs
(C)buccal cavity
(D)All of these
Embryologically, the body of cockroach is formed of 20 segments. What is the number in each region?
1. Head - 6; Thoracic - 3; Abdominal - 11
2. Head - 1; Thoracic - 3; Abdominal - 10
3. Head - 3; Thoracic - 3; Abdominal - 11
4. Head - 0; Thoracic - 3; Abdominal – 10
The presence of anal styles distinguishes male cockroaches from females. It is present on :
1. Ninth tergite
2. Ninth sternite
3. Tenth tergite
4. Tenth sternite