Which one of the following is not a characteristic of an insect-pollinated plant?
- A.Brightly coloured and fragrant flowers
- B.Light and small pollen grains
- C.Sticky and/or spiny pollen grains
- D.Presence of nectar in a flower
Correct answer
Explanation
The correct answer is B, Light and small pollen grains. Light, small and dry pollen is a feature of wind-pollinated plants, not of plants that depend on insects. Insect-pollinated (entomophilous) flowers have to attract a visitor and then make the pollen travel on its body. So they are large or brightly coloured, often scented, and offer nectar as a reward. Their pollen is fairly large and sticky or spiny so that it clings to the hairs and legs of bees, butterflies and moths. Wind-pollinated (anemophilous) plants such as grasses, maize and wheat do the opposite: dull small flowers, no scent or nectar, and huge amounts of light, smooth pollen that the air can carry, with feathery stigmas to catch it. Option A is wrong because bright colour and fragrance are how these flowers draw insects. Option C is wrong because sticky or spiny pollen is exactly what helps it stick to an insect. Option D is wrong because nectar is the food reward that brings insects to the flower. Exam tip: insect pollination = colour, scent, nectar, sticky pollen; wind pollination = light, dry, abundant pollen.
Practice Questions
View allChlorophyll in photosynthetic prokaryotic bacteria is associated with
- A.plastids
- B.membranous vesicles
- C.nucleoids
- D.chromosomes
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Photosynthetic bacteria have no chloroplasts; their pigments sit on infoldings of the cell membrane that form vesicles or sacs, often called chromatophores.
Read the full explanation →Fat in human body is stored in
- A.Adipose tissue
- B.Red blood cells
- C.Muscle tissue
- D.Epithelial tissue
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Adipose tissue is a loose connective tissue whose cells, called adipocytes, are built to store fat. Each cell holds a large droplet of fat that pushes the nucleus and cytoplasm to one side.
Read the full explanation →Which one of the following is a metalloid ?
- A.Germanium
- B.Coke
- C.Iodine
- D.Sugar
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Germanium is a metalloid, an element whose properties lie between those of metals and non-metals. It is a hard, shiny, grey-white solid like a metal, yet it is brittle and conducts electricity far less well than a metal, which makes it a semiconductor.
Read the full explanation →A photon of X-ray has energy of 1 keV. A photon of visible radiation has energy of 3 eV. In this context, which one of the following statements is not correct?
- A.The wavelength of X-ray photon is less than the wavelength of visible radiation photon.
- B.Both the photons have different energies.
- C.The speeds of both the photons in vacuum are different.
- D.The frequency of X-ray photon is higher than the frequency of visible radiation photon.
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This statement is wrong because every photon, whatever its energy, travels in vacuum at the same speed of light, about 3 × 10^8 metres per second.
Read the full explanation →Which of the following substances cause temporary hardness in water?
1. Mg(HCO3)2
2. Ca(HCO3)2
3. CaCl2
4. MgSO4
Select the correct answer using the code given below.
- A.3 and 4
- B.2 and 3
- C.1 and 4
- D.1 and 2
Show answer
Temporary hardness is caused by the bicarbonates of magnesium and calcium, Mg(HCO3)2 and Ca(HCO3)2. It is called temporary because simple boiling removes it: on heating, the soluble bicarbonates break down into insoluble carbonate or hydroxide, carbon dioxide and water, and the solid settles out.
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