Ques:Q: What is the name of the temporary organ that begins to form from the trophoblast layer of cells shortly after implantation? Read this paragraph and choose the correct option from the provided answers: The placenta is a temporary organ that begins to form from the trophoblast layer of cells shortly after implantation. (For an animation showing how the placenta forms, go to link below. ) The placenta continues to develop and grow to meet the needs of the growing fetus. A fully developed placenta, like the one in Figure above , is made up of a large mass of blood vessels from both the mother and fetus. The maternal and fetal vessels are close together but separated by tiny spaces. This allows the mother's and fetus's blood to exchange substances across their capillary walls without the blood actually mixing. Choices: - uterus - embryo - appendix - placenta A:

Ans:placenta
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Ques:Q: What are the two most common silicates? Read this paragraph and choose the correct option from the provided answers: Feldspar and quartz are the two most common silicates. In beryl, the silicate pyramids join together as rings. Biotite is mica. The silicate pyramids come together to create thin, flexible sheets. Compare the beryl and the biotite pictured below ( Figure below ). Choices: - Analcime and Feldspar - Petalite and Quartz - Petalite and Analcime - feldspar and quartz A:

Ans:feldspar and quartz
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Ques:Q: Which nervous system consists of all the nervous tissue that lies outside the central nervous system? Read this paragraph and choose the correct option from the provided answers: The peripheral nervous system (PNS) consists of all the nervous tissue that lies outside the central nervous system. It is shown in yellow in Figure below . It is connected to the central nervous system by nerves. A nerve is a cable-like bundle of axons. Some nerves are very long. The longest human nerve is the sciatic nerve. It runs from the spinal cord in the lower back down the left leg all the way to the toes of the left foot. Like the nervous system as a whole, the peripheral nervous system also has two divisions: the sensory division and the motor division. Choices: - auxiliary nervous system - significant nervous system - function nervous system - peripheral nervous system A:

Ans:peripheral nervous system
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Ques:Q: Solvation involves surrounding ions with what? Read this paragraph and choose the correct option from the provided answers: Solvation involves surrounding ions with solvent particles. Choices: - proteins - molecules - passive particles - solvent particles A:

Ans:
solvent particles
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