A) In a straight-chain molecule, all the carbon atoms are lined up in a row like cars of a train. The carbon atoms form the "backbone" of the molecule. B) In a branched-chain molecule, at least one of the carbon atoms branches off from the backbone. C) In a cyclic molecule, the chain of carbon atoms is joined at the two ends to form a ring. Each ring usually contains just five or six carbon atoms, but rings can join together to form larger molecules. A cyclic molecule generally has higher boiling and melting points than straight-chain and branched-chain molecules. Mark works as a scientist for a molecular research institute. Today, he has three samples of molecule in front of him, sample A, sample B, and sample C. Sample A is a straight-chain molecule; sample B is a branched-chain molecule; and sample C is a cyclic molecule. Mark's job is to determine the characteristics of each sample. In which sample no carbon atom would branch off, sample A or sample B?
Ans: sample A

Another obvious change that occurs during puberty is rapid growth. This is called the adolescent growth spurt . In boys, it is controlled by testosterone. The rate of growth usually starts to increase relatively early in puberty. At its peak rate, growth in height is about 10 centimeters (almost 4 inches) per year in the average male. Growth generally remains rapid for several years. Growth and development of muscles occur toward the end of the growth spurt in height. Muscles may continue to develop and gain strength after growth in height is finished. Joseph and Walter are two brothers who have always gotten along well, but are now going to be separated for the first time in their lives. Walter has just graduated high school and is going off to live at college several states away from home. Joseph is about to be a freshman in high school, so he has several years before he will even have the possibility of going off to the same college as his brother. Which boy's height will increase less over the next year?
Ans: Walter

Chemical equilibrium was studied by French chemist Henri Le Chatelier (1850-1936), and his description of how a system at equilibrium responds to a change in conditions has become known as Le Chatelier's principle . This principle states that when a chemical system is at equilibrium and is disturbed by a stress, the system will respond by attempting to counteract that stress until a new equilibrium is established. Stresses to a chemical system include changes in the concentrations of reactants or products, changes in the temperature of the system, or changes in the pressure of the system. We will discuss each of these stresses separately. In each case, the change to the equilibrium position will cause either the forward or reverse reaction to be favored over the opposite process. When the forward reaction is favored, the concentrations of the products increase, and the concentrations of the reactants decrease. When the reverse reaction is favored, the concentrations of the products decrease, and the concentrations of the reactants increase. John was trying to reenact Le Chatelier's principle. To that end, he conducted four tests, test A, test B, test C, and test D. In test A, he didn't input any stress to a chemical system in equilibrium. But In test B, he put some stress to the same system. In test C, he observed a forward reaction, but in test D, he observed a reverse reaction. Which test saw higher concentrations of the products, test C or test D?
Ans: test C

Farsightedness, or hyperopia, is the condition in which distant objects are seen clearly, but nearby objects appear blurry. It occurs when the eyeball is shorter than normal (see Figure below ). This causes images to be focused in a spot that would fall behind the retina (if light could pass through the retina). Hyperopia can be corrected with convex lenses. The lenses focus images farther forward in the eye, so they fall on the retina instead of behind it. Two siblings Jane and Matt, needed eyeglasses. Matt was nearsighted, while Jane was farsighted. they bought themselves two nice pairs of eyeglasses. Which sibling had hyperopia?
Ans: Jane