There is a theory that gravity could pull galaxies back together, causing a reverse big bang. Which observation makes this theory less likely than the idea that the universe may continue to expand?

Describe how alleles and genes are related

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.

What is the most common structure of volcanoes?