A flower typically is composed of:
- A.Stomata, Cotyledon, Petals, Sepals
- B.Carpels, Sepals, Petals, Cambium
- C.Carpels, Stamens, Petals, Sepals
- D.Petals, Sepals, Perianth, Root cap
Correct answer
Explanation
The correct answer is C, Carpels, Stamens, Petals, Sepals. A typical flower has four whorls arranged on the thalamus: sepals on the outside, then petals, then stamens, and carpels at the centre. The sepals together form the calyx, which is usually green and protects the flower in bud. The petals form the corolla, which is often brightly coloured to attract pollinators. The stamens, each with a filament and an anther, form the androecium, the male part that makes pollen. The carpels, each with a stigma, style and ovary, form the gynoecium or pistil, the female part that contains the ovules. Sepals and petals are the accessory whorls; stamens and carpels are the essential, reproductive whorls. Option A is wrong because stomata are pores on leaves and the cotyledon is a seed leaf; neither is a part of a flower. Option B is wrong because the cambium is a growth tissue in stems and roots, not a floral whorl. Option D is wrong because the root cap protects the root tip, and perianth is only a name for sepals and petals that cannot be told apart. Exam tip: calyx, corolla, androecium, gynoecium, from outside in.
Practice Questions
View allEqual volumes of all gases, under the same conditions of temperature and pressure, contain an equal number of molecules. This statement is known as
- A.Avogadro's law
- B.Boyle's law
- C.Charles's law
- D.Dalton's law of partial pressures
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It is the reason one mole of every gas occupies the same 22.4 litres at standard temperature and pressure, and it allowed chemists to settle the formulae of gases such as hydrogen and oxygen as having two atoms each.
Read the full explanation →Carbon forms two oxides, carbon monoxide and carbon dioxide, in which twelve grams of carbon combines with sixteen grams and thirty two grams of oxygen respectively. This illustrates
- A.The law of conservation of mass
- B.The law of constant proportions
- C.The law of multiple proportions
- D.Avogadro's law
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When two elements form more than one compound, the masses of one element that combine with a fixed mass of the other bear a simple whole number ratio, and here the oxygen masses of sixteen and thirty two grams for the same twelve grams of carbon are in the ratio…
Read the full explanation →How many moles are present in 36 grams of water?
- A.One mole
- B.Two moles
- C.Three moles
- D.Half a mole
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The molecular mass of water is eighteen unified atomic mass units, two hydrogen atoms of 1 u each and one oxygen atom of 16 u, so one mole of water weighs eighteen grams.
Read the full explanation →One unified atomic mass unit, written as u, is defined as
- A.The mass of one hydrogen atom
- B.One twelfth of the mass of one atom of carbon twelve
- C.One sixteenth of the mass of one atom of oxygen
- D.The mass of one electron
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This standard was adopted so that the atomic masses of all elements could be compared on one relative scale, and on it hydrogen comes out as about 1 u, oxygen as 16 u and chlorine as 35.5 u. Option A is wrong because the hydrogen atom was the standard in…
Read the full explanation →At standard temperature and pressure, the volume occupied by one mole of any gas is
- A.11.2 litres
- B.22.4 litres
- C.24.4 litres
- D.1 litre
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It follows from Avogadro's law: since equal volumes of all gases at the same temperature and pressure contain an equal number of molecules, one mole of hydrogen, of oxygen or of carbon dioxide all take up the same space at standard temperature and pressure, even though their masses are two…
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