Q: What are all cells surrounded by?


Read this paragraph and choose the correct option from the provided answers:

Heat waves have increased in frequency and duration in recent years. The summer 2011 North American heat wave brought record temperatures across the Midwestern and Eastern United States. Many states and localities broke records for temperature and for the most days above 100 o F.

 Choices:

- cytoplasm

- cell substrate

- amino acids

- cell membrane


A:
cell membrane