Here's why:

* Pollen is the male reproductive cell of a flower. Flowers need to receive pollen from other flowers of the same species to fertilize their eggs and produce seeds.

* Insects and wind act as pollinators. They carry pollen from one flower to another.

* Flowers have evolved various adaptations to catch pollen. These include:

* Bright colors and scents to attract insects.

* Sticky stigmas (the female part of the flower) to trap pollen.

* Large, feathery stigmas to catch wind-borne pollen.

So, flowers are the structures that catch pollen to enable reproduction.