Answer:
Spiral Galaxies, Elliptical Galaxies & Irregular Galaxies
Explanation:
How did galaxies originate? Astronomers believe that after the big bang, the explosion which began the universe 10 billion to 20 billion years ago, gravity began to compress masses of free-floating gas. Two main theories, bottom-up and top-down, explain what happened next. According to bottom-up theories, clusters began to form and assembled together into the larger units we know as galaxies. Top-down theories suggest that galaxies formed first, and the stars and other objects within them were subsequently produced. They categorized different galaxies to maintain their tests from the other galaxies.
Answer:
Water channel proteins help molecules move through a cell membrane.
Answer:
True
Explanation:
Oil and petroleum don't last forever
By squeezing the food and pushing it towards the digestive juices in your stomach
I think B is the answer The Clean Air Act That prevented air pollution and protected the ozone layer as well as promote public health. This act gave Enviromen. Protection Agency the power to take effective action fighting environmental air pollution