Vivipary is defined as germination
Answer: B
Vivipary is germination of the seed while it is still on the parent plant, within the fruit.
Mangroves show it: the seedling develops a long pointed radicle and drops into the mud already rooted, an adaptation to soil that is waterlogged and saline.
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Which of the following is an Autoimmune disease?
Answer: A
Systemic lupus erythematosus is an autoimmune disease.
The immune system makes antibodies against the body's own nuclear material, and the resulting inflammation affects skin, joints, kidneys, heart and brain. Anaphylaxis and farmer's lung are allergic rather than autoimmune.
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The human heart is
Answer: B
The human heart is myogenic - the beat originates in the heart muscle itself.
The sino-atrial node, a patch of specialised muscle in the right atrium, generates the impulse and sets the rate. Nerves only speed or slow it. An arthropod heart, by contrast, is neurogenic and stops if its nerve supply is cut.
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How many eyes are found in an earthworm?
Answer: C
The earthworm has no eyes.
Living underground it has no use for them. It detects light through photoreceptor cells scattered in the skin, densest at the front end, which is enough to make it retreat from the surface into its burrow.
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The enzyme that is necessary to bring about clotting of blood is
Answer: D
Thrombokinase (thromboplastin) starts the clotting of blood.
Released from damaged tissue and from platelets, it converts prothrombin into thrombin in the presence of calcium; thrombin then turns soluble fibrinogen into the insoluble fibrin mesh of the clot.
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The rate of heartbeat is accelerated by the hormone
Answer: A
Adrenaline accelerates the heartbeat.
Released from the adrenal medulla, it acts on the sino-atlantic pacemaker and the cardiac muscle to raise both rate and force, part of the fight-or-flight response. Acetylcholine, from the vagus, slows the heart.
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13 - Chambered heart occurs in
Answer: D
The cockroach has a thirteen-chambered heart.
It runs along the mid-dorsal line of the body, and each chamber has a pair of openings, the ostia, through which the blood enters from the body cavity. The circulation is open: the blood bathes the organs directly.
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The corner of the cells of collenchyma tissue in plant are thickened due to deposition of _____
Answer: C
The corners of collenchyma cells are thickened with cellulose and pectin.
The thickening gives flexible mechanical support to young growing stems and leaf stalks, and because the cells are living and the wall not lignified, they can still stretch as the organ grows. Sclerenchyma, by contrast, is thickened with lignin and is dead.
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When during the Cell Cycle are Chromosomes visible?
Answer: B
Chromosomes are visible only during cell division.
Through interphase the DNA is dispersed as fine chromatin, too thin to resolve. It condenses at prophase into the compact rod-like chromosomes that can be seen and counted, and disperses again at telophase.
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Bone deformities occur due to the excess intake of
Answer: D
Excess fluorine causes bone deformity.
Skeletal fluorosis follows years of drinking water with more than about 1.5 mg of fluoride per litre: the bones thicken, the ligaments calcify and the spine and limbs bend. It is endemic in parts of Rajasthan, Andhra Pradesh and Gujarat.
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