*Question*
Answer the following question given this paragraph: At the end of the Precambrian, a mass extinction occurred. In a mass extinction , the majority of species die out. The Precambrian mass extinction was the first of six mass extinctions that occurred on Earth. It's not certain what caused this first mass extinction. Changes in Earth's geology and climate were no doubt involved. Q: What was the first mass extinction that occurred on earth? Choices: - late Devonian mass extinction - paleozoic mass extinction - proterozoic mass extinction - precambrian mass extinction A:
**Answer**
precambrian mass extinction

*Question*
Answer the following question given this paragraph: The physical state and properties of a particular compound depend in large part on the type of chemical bonding it displays. Molecular compounds , sometimes called covalent compounds, display a wide range of physical properties due to the different types of intermolecular attractions such as different kinds of polar interactions. The melting and boiling points of molecular compounds are generally quite low compared to those of ionic compounds . This is because the energy required to disrupt the intermolecular forces between molecules is far less than the energy required to break the ionic bonds in a crystalline ionic compound. Since molecular compounds are composed of neutral molecules, their electrical conductivity is generally quite poor, whether in the solid or liquid state. Ionic compounds do not conduct electricity in the solid state because of their rigid structure, but conduct well when either molten or dissolved into a solution. The water solubility of molecular compounds is variable and depends primarily on the type of intermolecular forces involved. Substances that exhibit hydrogen bonding or dipole-dipole forces are generally water soluble, whereas those that exhibit only London dispersion forces are generally insoluble. Most, but not all, ionic compounds are quite soluble in water. Table below summarizes some of the differences between ionic and molecular compounds. Q: What is another name for molecular compounds? Choices: - phenotype compounds - oxidized compounds - synthetic compounds - covalent compounds A:
**Answer**
covalent compounds

*Question*
Answer the following question given this paragraph: The fatty material inside the artery on the right is plaque. Notice how much narrower the artery has become. Less blood can flow through it than the normal artery. Q: What fatty material inside arteries can restrict blood flow in the artery? Choices: - marble - collagen - cholesterol - plaque A:
**Answer**
plaque

*Question*
Answer the following question given this paragraph: A third factor that affects the rate of dissolving is the size of solute particles. For a given amount of solute, smaller particles have greater surface area. With greater surface area, there can be more contact between particles of solute and solvent. For example, if you put granulated sugar in a glass of iced tea, it will dissolve more quickly than the same amount of sugar in a cube (see Figure below ). That's because all those tiny particles of granulated sugar have greater total surface area than a single sugar cube. Q: For a given amount of solute, do smaller particles have a greater or lesser surface area? Choices: - lesser - equal - neither - greater A:
**Answer**
greater