NDA (II) 2023 General Ability Test · Question 96 of 146

Correct — D, Egg → zygote; zygote → embryo; ovule → seed; ovary → fruit. All four transformations are right, and together they cover both halves of what happens after fertilisation. On the inner track, the egg fused with a male gamete becomes the zygote, and the zygote divides and differentiates into the embryo. On the outer track, the structures that housed it mature in step — the ovule that contained the egg becomes the seed, and the ovary that contained the ovules becomes the fruit. Holding the two tracks side by side is the whole skill this question tests, and no other option gets more than one pair right.

• (a)Ovule → fruit; egg → embryo; zygote → seed; ovary → egg — Every pair is displaced by one step. The ovule becomes the seed and not the fruit, the egg becomes the zygote before any embryo appears, the zygote becomes the embryo and not the seed, and the ovary becomes the fruit — it never produces an egg.
• (b)Embryo → egg; ovary → fruit; ovule → zygote; zygote → seed — Only the ovary and fruit pair holds. An embryo cannot turn back into an egg, an ovule matures into a seed rather than into a zygote, and the zygote becomes the embryo rather than the seed.
• (c)Ovary → fruit; zygote → egg; embryo → ovule; seed → fruit — Again only the ovary and fruit pair holds, and the remaining three run backwards. The egg gives the zygote, the ovule gives the embryo its home rather than the reverse, and the fruit encloses the seed instead of developing from it.

After double fertilisation, a flower converts itself into a fruit along two parallel lines. The cells that took part in fertilisation give the next generation — egg to zygote to embryo. The tissues that surrounded them give the packaging — ovule to seed, ovary to fruit. The remaining floral parts, the sepals, petals and stamens, usually wither and fall away once their work of attracting a pollinator is done.

The examiner has built this item so that three options each contain one true pair. That is deliberate — a student who spots 'ovary to fruit' in option (b) or (c) and stops reading will mark a wrong answer. The only safe method is to check all four pairs in an option before accepting it. It also helps to remember that these transformations are one-way; several of the wrong pairs here are simply the correct relation printed in reverse, such as 'zygote to egg' or 'seed to fruit'. A useful cross-check is that anything the seed or fruit is made from must have existed in the flower before fertilisation, which immediately rules out an ovary that produces an egg.

• The egg fertilised by a male gamete forms the zygote, and the zygote develops into the embryo.
• The ovule matures into the seed; the ovary matures into the fruit.
• In double fertilisation the second male gamete fuses with the polar nuclei to give the endosperm, which nourishes the embryo.
• In parthenocarpy the ovary develops into a fruit without fertilisation, which is how seedless fruits are produced.

• Accepting an option because the first pair in it is correct; three of the four options here contain one true pair.
• Missing that several wrong pairs are the right relation written backwards.
• Confusing the ovule with the ovary — one gives the seed, the other gives the fruit.

Asked as a combination item — every pair in the chosen option must be correct, not just the first one.

• practice — not a real PYQ

  After fertilisation in a flowering plant, the ovary develops into the

  • (a)seed
  • (b)fruit
  • (c)embryo
  • (d)endosperm

  Answer(b) fruit — the ovules inside it become the seeds.

• practice — not a real PYQ

  The development of a fruit without fertilisation is called

  • (a)parthenocarpy
  • (b)apomixis
  • (c)polyembryony
  • (d)vivipary

  Answer(a) parthenocarpy — it is used commercially to raise seedless fruits.