Enzymatic reactions: Degradation

Plz help me figure out what goes in the boxes!

What is thought to have caused the mass extinction at the end of the cretaceous period?

Acceleration is a direct result of a.) balanced forces b.) unbalanced forces c.) gravity d.) velocity hurry!

Which two factors contributed to creating a global culture? the creation of the united nations improvement in telecommunications health issues such as the ebola virus increased opportunities for global travel