Which of the following describes a difference between galaxies and solar systems? a. galaxies contain only moons, while solar systems contain planets. b. gravity holds solar systems in orbits but does not exist between stars in galaxies. c. a galaxy is a collection of millions of stars, while a solar system is a star and the planets around it. d. it's easier to use astronomical units to measure distances in the galaxy but use light years for measurements in a solar system.

The correct answer is Option C.

Explanation:

A galaxy is defined as the huge collection of gas, dust and billions of stars along with their solar system. All these systems are held together by the gravitational attraction. For Example: Milky Way.

A solar system is defined as the collection of a star, planets along with their moons, satellites of the planets, asteroids, meteoroids and comets. In the solar system planets revolve around the Star. For Example: Our Solar System has a star named Sun and eight planets revolve around it.

Hence, the correct answer is Option C.

electron microscopy and scanning tunneling microscopes gives us a greater understanding of atoms by being able to see the atom itself, and lets us see some atomic reactions.

explanation:

both adhesion and cohesion are attractions.

they are different in that adhesion is the force of attraction between the molecules of two different substances, whereas cohesion is the force of attraction between molecules of the same substance.

possible examples include capillary action, in which the adhesion between water and glass causes the water to rise in a narrow tube against the force of gravity.

because of hydrogen bonding, water is extremely cohesive.

this causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surfaces.

hope this .