21. When a person exercises, heart rate increases. Explain how increased blood flow helps maintain homeostasis during exercise.

Please someone help I’m stuck:(

Which particle controls what element an atom is?

How do the sperm cells get from the stigma to the ovules? a. they slide down the petals to the bottom of the flower. b. they travel through pollen tubes. c. they travel along filaments. d. insects carry the sperm cells from the stigma to the ovules.

Why should organisms reproduce more offspring than will survive? select all that apply.