QuestenaUn entraînement qui indique quoi revoir ensuite
RechercheCréer un test
Question 106

Wind-pollinated plants release enormous quantities of pollen. Which explanation of that quantity is correct?

  1. Every grain becomes a seed, so more grains means more seeds
  2. The extra grains feed the insects that visit the flower
  3. Wind pollen is heavy, so most of it drops straight to the ground
  4. Only a tiny fraction of the lightweight grains reaches a stigmaBonne réponse

Explication

Air carries grains in every direction with no aim whatever, so the chance that any one grain settles on a suitable receiving surface is tiny, and the plant compensates by releasing far more than it could ever need. Equating grains with seeds confuses the delivery vehicle with the result, since a grain contributes to a seed only if it happens to arrive and fertilisation then follows.

Continuer avec ce test

Commencer l’entraînement
Comprendre ce thème (≈5 min)Retour au test
Question 106: Wind-pollinated plants release enormous quantities of… · Plants and Photosynthesis · Questena