What biological phenomena of nature have you observed?

Biological phenomena are those changes that we observe in living organisms. For example, in the spring leaves bloom on the trees, fresh grass appears. Later you can see how flowers and various fruits are formed on plants. Withering processes are also a biological phenomenon. Therefore, we also attribute yellowed leaves and leaf fall to such phenomena. In the animal kingdom, everyone can observe the arrival of birds in the spring, or, conversely, how they fly away to warm regions.