What are three things petals do for a plant and why is it said that insects have co-evolved with angiosperms?

Question

What are three things petals do for a plant and why is it said that insects have co-evolved with angiosperms?

Answer 1

(1) I've heard petals provide a color signal to bees and other insects that their "airport" is open and ready for nectar.

(2) Petals give off a scent to attract animals and insects to brush against them to spread seeds.

(3) The petals are part of the s*x organs for the plant!

Insects have co-evolved with angiosperms, and to me, it's like the chicken and the egg problem. Without insects, these flowers wouldn't reproduce, and without flowers, the insects wouldn't have food. The way I look at it, is looking at the past. I don't remember how long ago, but when plants were evolving millions of years ago, they didn't have flowering plants yet, but yet they had insects. Where did insects get their food back then? Maybe they ate the fern leaves, or ate each other. Somehow over a long period of time, the dinosaur plants found it useful for the bugs to spread their seeds for them, so the flowering plants evolved (not immediately) and as more and more bugs used flowering plants, more different species of flowers grew.