If the galaxy is observed over time, which of the following observations would most strongly suggest that gravitational forces are acting throughout it? A. supernovae explosions B. the expansion of the universe C. the expansion of the galaxy D. the rotation of the galaxy

In the water cycle , when does water undergo a chemical change

Which best describes this behavior? it is beneficial only to the males that do not fertilize eggs. it is beneficial only to the female workers that are not fertilized. it is beneficial to each one of the individual colony members. it is beneficial to the whole species, but not to all of the individual members.

The eruption of a nearby volcano causes a prairie ecosystem to receive a lot less sunlight. which of these is most likely effect on the ecosystem?