Maintaining a stable internal environment within the body is called:

Arrange the levels of organization from the smallest to the largest

Stratum corneum _____________________

Unit 2 INSTRUCTIONS: Rewrite the sentences using the present perfect. Ex: I waited for an hour.       I have waited for an hour. 

INSTRUCTIONS: Fill in the blank with the present perfect or the simple past. 

INSTRUCTIONS: Complete each sentence or question. Use the present perfect of the verb in parentheses.  Ex: Nick has made (make) three phone calls this morning. 

Why ____________ there so many English speakers today?

INSTRUCTIONS: Complete each sentence or question with the simple past form of the verb in parentheses. Use contractions wherever possible. Ex. I didn’t drive (drive) to school. I took the bus.

Monica ________ (lose) her wallet this morning. 

My friends and I ____________ (speak) English together.