Answer the following question given this paragraph: The deadly nerve gas Sarin irreversibly inhibits acetycholinesterase. What effect would Sarin have on muscle contraction? After depolarization, the membrane returns to its resting state. This is called repolarization, during which voltagegated sodium channels close. Potassium channels continue at 90% conductance. Because the plasma membrane sodiumpotassium ATPase always transports ions, the resting state (negatively charged inside relative to the outside) is restored. 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 refractory period. During the refractory period, the membrane cannot generate another action potential. The refractory period allows the voltage-sensitive ion channels to return to their resting configurations. The sodium potassium ATPase continually moves Na+ back out of the cell and K+ back into the cell, and the K+ leaks out leaving negative charge behind. Very quickly, the membrane repolarizes, so that it can again be depolarized. 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
Answer the following question given this paragraph: Modern seed plants include gymnosperms and angiosperms. Q: Gymnosperms and angiosperms are types of _________ seed plants. Choices: - heritage - extinct - genetic - modern A:
modern
Q: Answer the following question given this paragraph: Vertebrates have an adaptive immune system. The immune system is the organ system that defends the body from pathogens and other causes of disease. Being adaptive means that the immune system can learn to recognize specific pathogens. Then it can produce tailor-made chemicals called antibodies to attack them. This allows the immune system to launch a rapid attack whenever the pathogens invade the body again. 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: Answer the following question given this paragraph: There are many other nervous system diseases. They include multiple sclerosis, Huntington's disease, Parkinson's disease, and Alzheimer's disease. However, these diseases rarely, if ever, occur in young people. Their causes and symptoms are listed below ( Table below ). The diseases have no known cure, but medicines may help control their symptoms. 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*
Answer the following question given this paragraph: Most scientists agree that global warming is caused by more carbon dioxide in the atmosphere (see Figure below ). This increases the greenhouse effect. There is more carbon dioxide mainly because of the burning of fossil fuels. Destroying forests is another cause. With fewer forests, less carbon dioxide is removed from the atmosphere by photosynthesis. 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).
Answer the following question given this paragraph: A suspension is a heterogeneous mixture in which some of the particles settle out of the mixture upon standing. The particles in a suspension are far larger than those of a solution and thus gravity is able to pull them down out of the dispersion medium (water). The typical diameter for the dispersed particles (the sand) of a suspension is about 1000 times greater than those of a solution (less than approximately two nanometers for particles in solution, compared to greater than 1000 nanometers for particles in suspension). Unlike in a solution, the dispersed particles can be separated from the dispersion medium by filtering. Suspensions are heterogeneous because at least two different substances in the mixture can be identified. 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