Which statement is true about the scientific method? it follows one prescribed sequence of steps. it begins and ends with an experiment. it is used only in earth and space science. it can be cyclic.

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.

Achange in which factor will affect the rate of reaction only when gases are involved? temperature pressure surface area concentration

1. in what ways have non-native species been beneficial? 2. what are some of the hypotheses for the collapse of honeybee colonies? 3. distinguish between regional and functional extinction. 4. why is it difficult to measure background extinction rates? 5. what three factors are most important in causing extinction rates to climb?