Flowers enable pollen from one plant can fertilise ovules of another plant. This is called cross-fertilisation and helps create a greater variety in the plants. Variety aids survival as usually some plants will adapt and live in any new conditions. Some plants produce separate male and female flowers, but most plants have flowers containing both male and female reproductive parts. Stamens are the male parts and carpels are the female parts.
Some flowers are complex or multiple as in the dandelion.
Study the different parts of a simple flower as shown below.