Which kind of wave would be observed in outer space between planets , where there is very little matter ? a . an electromagnetic wave , such as an x-ray b. an electromagnetic wave , such as a sound wave . c. a mechanical wave , such as an x-ray . d . a mechanical wave , such as a sound wave .

A

Explanation:

Mechanical waves, such as sound, cannot be transmitted in vacuum, unlike electromagnetic waves. In space, one is able to observe supernovas but no sound blast can be heard. Examples of electromagnetic waves are the gamma rays, X rays, visible light and radio waves.

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?