Do mollusks change their shell several times throughout their life

This is the process of making a prediction based on the results of prior observations of similar events.

How energy flows through each level in this energy pyramid. is all the matter and energy from one level transferred to the next level?

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled