571: The human body is immune to which of the following diseases?
(a) Smallpox
(b) Diabetes
(c) Tuberculosis
(d) jaundice
572: Human activities in the recent past have caused the increased concentration of carbon dioxide in the atmosphere, but a lot of it does not remain in the lower atmosphere because of
1. Its escape into the outer strato-sphere.
2. The photosynthesis by phyto-plankton in the oceans.
3. The trapping of air in the polar ice caps
Which of the statements given above is/are correct?
(a) 1 and 2
(b) 2 only
(c) 2 and 3 only
(d) 3 only
Explanation:
Much of the carbon dioxide produced by humans does not stay in the atmosphere but is stored in the oceans or on land in plants and soils. By far the largest carbon store on Earth is in sediments, both on land and in the oceans, and it is held mainly as calcium carbonate (CaCO3).
Carbon dioxide is also taken up by phytoplankton in photosynthesis and converted into plant material. Land plants and marine phytoplankton take up about the same amounts of carbon dioxide as each other but marine phytoplankton grow much much faster than plants.
573: Fruits stored in a cold chamber exhibit longer storage life because
(a) exposure to sunlight is prevented
(b) concentration dioxide in the is increased of carbon environment
(c) rate of respiration is decreased
(d) there is an increase in humidity
Explanation:
Respiration a process by which fruits and vegetables convert sugars into carbon dioxide, water, and heat.
Metabolic activity in fresh fruits and vegetables continues for a short period after harvest.
The energy required to sustain this activity comes from the respiration process.
Thus by storing fruits in a cold chamber reduces the rate of respiration and it lasts for longer period.
Hence option (c) is correct.
574: Temperature in human beings is controlled by:
(a) Pituitary gland
(b) Thyroid gland
(c) Hypothalamus gland
(d) Adrenal gland
575: Mica is abundantly used in which of the following industries?
(a) Cement
(b) Electrical
(c) Plastic
(d) Fire resistance bricks