Which piece of evidence provides the strongest support for the claim that a roller coaster is a "great application of potential energy to generate a massive amount of kinetic energy"? a. roller coasters are designed to be thrilling but bring people back down by the end safely. b. the thrills of a roller coaster are based on a person experiencing changes in potential energy and kinetic energy. c. some riders find roller coasters to be thrilling, but others find them to be scary. d. many people will wait up to 50 minutes in line to experience the thrills of a roller coaster.

i think its c but correct me if im wrong

the present continuous is a verb tense which is mainly used to indicates that an action is in progress at the moment of speaking.  

it is formed using: person + verb to be (am/is/are) +verb + - ing form  

example: i am studying at this moment .

in addition, the present continuous is also used in order to express things that will or will not happen in the near future.

example: i am having dinner with some friends tonight.

the speaker sometimes   uses it   to express that an action is repeated and it causes irritation on the part of the speaker

example: my sister is constantly complaining about everything.