Question

1. what process do some plants use to flower at the same time every year?

senescence
abscission
photoperiodism

Explanation:

• Senescence refers to the aging process in plants, not related to flowering time.
• Abscission is the shedding of leaves, fruits, etc., not about flowering annually.
• Photoperiodism is the response of plants to the length of day and night, which helps them flower at specific times (like same time every year).

Answer:

photoperiodism