Decide if the "personal a" is necessary in the following sentence. Tengo dos amigos. The "personal a" is necessary. The "personal a" is not necessary.

Did the universe cool off or get hotter as it expanded after the 'big bang"?

This graph represents four ecosystems. each ecosystem has a different number of species, adding to its biodiversity. different colors represent different species. which statements correctly summarize the data depicted by the graph? 1. ecosystem d has more biodiversity than ecosystem c. 2. ecosystem b has more biodiversity than all the other ecosystems. 3. ecosystem a has more biodiversity than ecosystem b but less biodiversity than ecosystem c. 4. ecosystem b has more biodiversity than ecosystems c and d but less biodiversity than ecosystem a. 5. ecosystem a has more biodiversity than ecosystem c but less biodiversity than ecosystem b.

Which object has the least amount of kinetic energy? a. a car driving down a road b. a soccer ball rolling down a hill c. a bicycle locked to a bike rack d. a satellite orbiting earth