Question

What is the main idea of these two sentences?

Many flowers are what we call annuals, their entire life cycle — from seed to death — takes just one year. They might leave behind sleeping seeds that could sprout again in the future, but the flowers, roots, stems and leaves all fade away as soon as the season is done.
Annuals only live for one year and will not return.
The life cycle of a plant is seed to death
Plants have flowers, root systems, stems, and leaves.
Scientists think annuals are the first type of plant that existed.

Answer 1

the season is done.

Annuals only live for one year and will not return.

The life cycle of a plant is seed to death

Plants have flowers, root systems, stems, and leaves.