Seed plants are either annuals, biennials or perennials, based on their life cycle.
(Seed plants; are; either annuals, biennials or perennials, based on their life cycle) (either annuals, biennials or perennials; based; on their life cycle)
Seed plants either annuals, biennials or perennials
are based
either annuals, biennials or perennials, based on their life cycle
on their life cycle