What is released when an excited electron returns to a lower energy state?
an isotope
a proton
electricity
electromagnetic radiation

The first signs of cellular differentiation occur in the blastocyst. why is cellular differentiation important for the development of a fully formed human infant?

Imagine a rocket launching from earth and travelling to the moon. in which order would the rocket pass through the layers of the atmosphere? thermosphere, mesosphere, stratosphere, troposphere troposphere, mesosphere, stratosphere, troposphere thermosphere, stratosphere, mesosphere, troposphere troposphere, stratosphere, mesosphere, thermosphere

2. given that most biochemical (other than coal) rocks react with hydrochloric acid, what does that tell you about organisms?