Q: How does a cell's membrane keep extracellular materials from mixing with it's internal components? Choices: - absorbs extracellular materials - repels extracellular materials - destroys extracellular materials - provides a barrier A:
provides a barrier

Q: Viruses depend on what type of cells? Choices: - blood cells - immune system cells - anchor cells - host cells A:
host cells

Q: What is the area of our universe that isn't stars and galaxies called? Choices: - nebula - solar systems - galaxies - dark matter A:
dark matter