*Question*
Q: What occurs when the immune system attacks harmless substances that enter the body from the outside? Choices: - cell rejection - anomalies - mutation - allergies A:
**Answer**
allergies

*Question*
Q: What is named after the type of enzyme they interact with in the cell? Choices: - oxygen proteins - function proteins - nitrogen proteins - receptor proteins A:
**Answer**
receptor proteins

*Question*
Q: When a supercooled liquid boils, the temperature drops as the liquid is converted to what? Choices: - carbon - solid - atoms - vapor A:
**Answer**
vapor

*Question*
Q: Most people can survive only a few days without what essential substance? Choices: - air - food - carbon - water A:
**Answer**
water