A and B secrete their hormones when they receive orders from gland C. Which of the following can A, B and C respectively be?
- A.Pancreas, Adrenal glands, Thyroid
- B.Thyroid, Adrenal glands, Pituitary
- C.Testes, Ovaries, Thyroid
- D.Pituitary, Pancreas, Thyroid
Correct answer
Explanation
The correct answer is B, Thyroid, Adrenal glands, Pituitary. The pituitary gland sends out hormones that order the thyroid and the adrenal glands to release their own hormones. The pituitary is a pea-sized gland attached to the base of the brain, and it is called the master gland because it controls several other endocrine glands. For example, it releases a thyroid-stimulating hormone that makes the thyroid produce thyroxine, and another hormone that makes the adrenal glands release theirs. NCERT's Class 8 science book notes that glands such as the thyroid and the adrenals secrete hormones on receiving a message from the pituitary. A is wrong because the pancreas releases insulin in response to blood sugar, and the thyroid does not command the other two. C is wrong because the testes and ovaries take their orders from the pituitary, not from the thyroid. D is wrong because the pituitary gives orders; it does not wait for orders from the thyroid. Exam tip: pituitary, master gland; thyroid, thyroxine; adrenal, adrenaline; pancreas, insulin.
Practice Questions
View allThe fact that the planets move around the Sun, not in circles but in ellipses, was first demonstrated by
- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
Read the full explanation →Which one of the following statements is correct?
- A.Urea is produced in liver.
- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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Liver cells turn the toxic ammonia released from the breakdown of amino acids into urea through the ornithine cycle, also called the urea cycle.
Read the full explanation →Which one of the following is the correct sequence of passage of light in a compound microscope?
- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Light passes through the condenser to the specimen, is picked up by the objective lens, travels up the body tube and reaches the eye through the eyepiece.
Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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It binds oxygen at its iron-containing haem groups and carries some carbon dioxide on its protein chains. Each haemoglobin molecule has four polypeptide chains and four haem groups, and each haem iron can hold one oxygen molecule, forming oxyhaemoglobin in the lungs.
Read the full explanation →Which one of the following statements regarding histone proteins is correct?
- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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They are the proteins around which DNA winds to form chromatin in the nucleus of eukaryotic cells. Histones are small basic proteins, rich in the positively charged amino acids lysine and arginine, which attract the negatively charged phosphate groups of DNA.
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