Q: The period immediately following the transmission of an impulse in a nerve or muscle, in which a neuron or muscle cell regains its ability to transmit another impulse, is called the ______ period. Choices: - activation - extraction - interstitial - refractory A:
refractory

Q: Gymnosperms and angiosperms are types of _________ seed plants. Choices: - heritage - extinct - genetic - modern A:
modern

Q: Q: Which organ system defends the body from pathogens and other causes of disease? Choices: - digestion system - nervous system - respiratory system - immune system A:
A: immune system

Question: Q: Multiple sclerosis, huntington's disease, parkinson's disease, and alzheimer's disease are example of diseases of which body system? Choices: - muscular system - lymphatic system - circulatory system - nervous system A:
Answer: nervous system

*Question*
Q: The abundance of this substance in the atmosphere is what most scientist agree that is causing global warming? Choices: - argon - iron oxide - liquid dioxide - carbon dioxide A:
**Answer**
carbon dioxide

(Q).
Q: What do you call a mixture in which some particles settle out of it when it is left standing? Choices: - emulsion - alloy - homogenous - suspension A:
(A).
suspension