111: Some species of plants are insectivorous. Why?
(a) Their growth in shady and dark places does not allow them to undertake sufficient photosynthesis and thus they depend on insects for nutrition
(b) They are adapted to growing nitrogen deficient soils and thus depend on insects for sufficient nitrogenous nutrition
(c) They cannot synthesize certain vitamins themselves and depend on the insects digested by them
(d) They have remained in that particular stage of evolution as living fossils, a link between autotrophs and heterotrophs
Explanation:
An insectivorous plant, also called a carnivorous plant, captures prey items, such as insects, spiders, crustaceans, mites, and protozoans, as a nitrogen source. Many insectivorous species live in freshwater bogs, where nitrogen is not present in available form, because the pH of the water is extremely acid. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic bogs and rock outcroppings.
112: The gas used for artificial ripening of green fruits is
(a) Carbon dioxide
(b) Ethane
(c) Hydrogen
(d) acetylene (ethyne)
113: What is the difference between asteroids and comets?
1. Asteroids are small rocky planetoids, while comets are formed of frozen gases held together by rocky and metallic material.
2. Asteroids are found mostly between the orbits of Jupiter and Mars, while comets are found mostly between Venus and Mercury.
3. Comets show a perceptible glowing tail, while asteroids do not.
Which of the statements given above is / are correct?
(a) 1 and 2 only
(b) 1 and 3 only
(c) 3 only
(d) 1, 2 and 3
Explanation:
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones. The term asteroid has come increasingly to refer specifically to the small rocky-icy and metallic bodies of the inner Solar System out to the orbit of Jupiter. They are grouped with the outer bodies - centaurs, Neptune trojans, and trans-Neptunian objects-as minor planets, which is th term preferred in astronomical circles. A large majority of known asteroids orbit in the asteroid belt between the orbits of Mars and Jupiter or co-orbital with Jupiter (the Jupiter Trojans).
Comets are small, fragile, irregularly shaped bodies composed of a mixture of non-volatile grains and frozen gases. They have highly elliptical orbits that bring them very close to the Sun and swing them deeply into space, often beyond the orbit of Pluto i.e. kupier belt.
Tracking comets is relatively easy for the amateur astronomer, as comets show little perceptible motion from night to night, and many are visible with the naked eye, whereas asteroids do not show any such tail.
114: Which one of the following plants can fix nitrogen from air?
(a) Rice
(b) Wheat
(c) Pea
(d) Maize
115: Chemical composition of pearl is:
(a) Calcium carbonate
(b) Calcium carbonate and magnesium carbonate
(c) Calcium sulphate
(d) Calcium chloride