INSTRUCTIONS: Complete each sentence with the words in parentheses. Use the present perfect, the present perfect continuous, or the simple past of the verb. ____________________ (Rita / buy) a new car last week.

INSTRUCTIONS: Unscramble the words to make past perfect sentences.never / seen / had / they / an alligator

INSTRUCTIONS: Rewrite the sentences. Use the passive voice and by to identify the agent—the person who performed the action.The judge gave out prizes.

INSTRUCTIONS: Complete each sentence. Use the passive of the verb in parentheses with get. Forty employees ____________________ (lay off) last month.

Select the correct equation for the sum of the torques on the lever arm. 

This is a factor in an experiment that the scientist actually manipulates or that varies systematically across subjects. This variable is also most often plotted on the X-axis of a graph.

Homeostasis is the body’s ability to …

For each definition below, select the best functional category of proteins from the pull-down menus.

INSTRUCTIONS: Complete each sentence with the correct participle in parentheses. I was _______________ (amazing / amazed) at how good his acting was.

Activation energy is …