Question

Which of the following constitutes a pistil?
(a) Stigma, anther, and ovary
(b) Stigma, stamen, and ovary
(c) Pollen sac, style, and ovule
(d) Stigma, style, and ovary

Answer 1

Hint: The gynoecium (is the female reproductive part of the flower) consists of one or more separate pistils. The pistils consist of the pollen-receptive tip, a stalk, and a swollen base.
A pistil consists of three parts and they are stigma, style, and ovary.

Complete answer:
Stigma the part where pollen germinates and is part of the pistil. The stigma is the receptive tip of several fused carpels of a carpel in the flower. Stigmas are the landing zone or the entrance; they are adapted to trap pollen with hairs, flaps, and other surfaces to increase their efficiency. Sometimes stigmas are covered with a waxy, sticky substance for trapping the pollen.
Stylethe stalk of the pistil connects the ovary to the stigma. When pollen reaches the flower, it begins to grow a tube through the style which will eventually reach the ovary. It is the location where pollen tubes travel to deliver sperm cells to the egg, this way it helps fertilization. Also, style acts as a buffer since only compatible pollen can grow a pollen tube.
Ovary is the expanded basal part, on which the style is present and it is an organ of the female reproductive part of flower or gynoecium. It holds the ovule. A ripened ovary of a plant containing seeds is the fruit.
So, the correct answer is 'Stigma, style, and ovary'.

Note: In plants, fertilization occurs when haploid gametes (pollen grain and egg) by certain agents meet to create a diploid zygote. Fertilization takes place in the embryo sac. The oval structure present in the ovule of flowering plants is known as the embryo sac or female gametophyte.