Astronomers use various forms of evidence to learn more about what early Earth was like. What are two objects astronomers have used?

Which of these questions might a character ask if the conflict is man versus self? a. which path should i take to better myself? b. which boulder will be too heavy for me to carry? c. which friend is going to ditch me today? d. all of the above

Acertain radio station broadcasts radio waves that have a wavelength of 298cm what is its broadcast frequency?

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?