Question

An example of a dioecious plant is
(a)Cucumber
(b)Maize
(c)Castor bean
(d)Date palm

Answer 1

Hint: Dioecious plants are the ones where the male and female reproductive systems occur on separate plants. These plants can only reproduce through pollination and both the parents are genetically different.

Complete answer:
Date palm is dioecious because these plants exclusively bear either male flowers or female flowers.
While both the dioecious plants produce flowers, one plant has only the male reproductive parts and the other plant has the female parts. A dioecious plant requires two separate plants, that is, a male and a female plant to successfully pollinate. Only the female plant bears the fruit. Some other well-known Dioecious plants include- Spinach, Juniper bushes, Sago, Mulberry, Ginkgo, Mistletoe, Papaya, Yam, Holly, Cloudberry, Asparagus, Hemp, Hop, Willow, Kiwifruit, Poplar, Currant Bushes, etc.

Additional Information:

 Monoecious plants are the one that has male and female flowers on the same plant or the ones that have flowers which contain both male and female reproductive components. Some examples of monoecious plants are birch, hazelnut, oak, pine, spruce, corn, and squashes. They do not need pollinating agents for the pollination. They usually undergo self-pollination i.e. Autogamy or pollination between male and female flowers of the same plant i.e. Geitonogamy.
So, the correct answer is ‘Date palm'.

Note:
For dioecious plants, the male and female plants must be present for pollination to occur. They pollinate through Xenogamy. In these plants, it is physically impossible to self-pollinate, so genetic diversity is guaranteed in them. Dioecy is seen in a wide variety of plant families especially the woody plants and heterotrophic species. Certain algae are also dioecious.