Answer the following question given this paragraph: The simplest organic compounds are those composed of only two elements: carbon and hydrogen. These compounds are called hydrocarbons. Hydrocarbons themselves are separated into two types: aliphatic hydrocarbons and aromatic hydrocarbons. Aliphatic hydrocarbons are hydrocarbons based on chains of C atoms. There are three types of aliphatic hydrocarbons. Alkanes are aliphatic hydrocarbons with only single covalent bonds. Alkenes are hydrocarbons that contain at least one CC double bond, and alkynes are hydrocarbons that contain a CC triple bond. Occasionally, we find an aliphatic hydrocarbon with a ring of C atoms; these hydrocarbons are calledcycloalkanes (or cycloalkenes or cycloalkynes). Aromatic hydrocarbons have a special six-carbon ring called a benzene ring. Electrons in the benzene ring have special energetic properties that give benzene physical and chemical properties that are markedly different from alkanes. Originally, the term aromatic was used to describe this class of compounds because they were particularly fragrant. However, in modern chemistry the term aromatic denotes the presence of a six-membered ring that imparts different and unique properties to a molecule. The simplest alkanes have their C atoms bonded in a straight chain; these are callednormal alkanes. They are named according to the number of C atoms in the chain. The smallest alkane is methane:. Q: The simplest organic compounds have hydrogen and what else? Choices: - sodium - oxygen - nitrogen - carbon A:
carbon
(Question)
Answer the following question given this paragraph: Q: What is the raw material for evolution by natural selection called? Choices: - pattern variation - mutation - comparable variation - genetic variation A:
(Answer)
genetic variation
Ques: Answer the following question given this paragraph: Did you notice that none of these statements relates to the identity of the gas? This means that all gases should behave similarly. A gas that follows these statements perfectly is called an ideal gas. Most gases show slight deviations from these statements and are called real gases. However, the existence of real gases does not diminish the importance of the kinetic theory of gases. One of the statements of the kinetic theory mentions collisions. As gas particles are constantly moving, they are also constantly colliding with each other and with the walls of their container. There are forces involved as gas particles bounce off the container walls (Figure 8.9 "Gas Pressure"). The force generated by gas particles divided by the. Q: Gases can be classifed as real or what? Choices: - noble - shape - dense - ideal A:
Ans: ideal
(Q).
Answer the following question given this paragraph: In addition to holding cells together, tight junctions play a role in the transport of materials. Tight junctions prevent the passage of molecules and ions through the space between cells. So these molecules and ions must actually enter cells (either by diffusion or active transport) in order to proceed through a tissue. This allows tight junctions to indirectly play a role over what substances are allowed into a specific cell. Tight junctions play this role in maintaining the blood-brain barrier. Q: What can prevent the passage of molecules and ions between cells, such as in the blood-brain barrier? Choices: - fatty junctions - solid junctions - special junctions - tight junctions A:
(A).
tight junctions
Ques:Answer the following question given this paragraph: Cellular respiration uses oxygen in addition to glucose. It releases carbon dioxide and water as waste products. Cellular respiration actually "burns" glucose for energy. However, it doesn't produce light or intense heat like burning a candle or log. Instead, it releases the energy slowly, in many small steps. The energy is used to form dozens of molecules of ATP. Q: In addition to glucose, what gas is used during cellular respiration? Choices: - methane - hydrogen - nitrogen - oxygen A:

Ans:oxygen
Answer the following question given this paragraph: The cis isomer has the two single hydrogen atoms on the same side of the molecule, while the trans isomer has them on opposite sides of the molecule. In both molecules, the bonding order of the atoms is the same. In order for geometric isomers to exist, there must be a rigid structure in the molecule to prevent free rotation around a bond. If the double bond in an alkene was capable of rotating, the two geometric isomers above would not exist. In addition, the two carbon atoms must each have two different groups attached in order for there to be geometric isomers. Propene has no geometric isomers because one of the carbon atoms has two single hydrogens bonded to it. Q: A molecule has two structures that can be generated. what is this called? Choices: - resonance hybrids - congruence - ethnocentrism - isomerism A:
isomerism