Given the background: Cholesterol has been implicated in heart disease for decades. Atherosclerosis is a disorder of the arteries in which cholesterol and other materials are deposited on the interior of the arterial wall. These deposits lead to the formation of plaques that can restrict or even block the flow of blood through these blood vessels (see Figure below ). A decrease in the flow of blood can lead to high blood pressure and a lowered oxygen supply to the heart muscle. A complete blockage of blood flow to parts of the heart (a heart attack) can cause significant damage due to oxygen deprivation, in some cases leading to death. and the situation: Brad and Dale went to the doctor for a check up. Brad did some blood tests and found out he has very high cholesterol levels, while his partner Dale had normal cholesterol levels, and was very healthy. Brad got scared and started worrying. Answer the following question: Which friend had less plaque on his blood vessels?
Ans: Dale

Given the background: Sometimes muscles and tendons get injured when a person starts doing an activity before they have warmed up properly. A warm up is a slow increase in the intensity of a physical activity that prepares muscles for an activity. Warming up increases the blood flow to the muscles and increases the heart rate. Warmed-up muscles and tendons are less likely to get injured. For example, before running or playing soccer, a person might jog slowly to warm muscles and increase their heart rate. Even elite athletes need to warm up ( Figure below ). and the situation: Two groups of runners attended a 5k event downtown. Brown group warmed up properly before the race, but Red group did no such thing and suffered the consequences. Answer the following question: Which group was less at risk for muscle injuries?
Ans: Brown

Given the background: While the Grants were on the Galapagos, a drought occurred. As a result, fewer seeds were available for finches to eat. Birds with smaller beaks could crack open and eat only the smaller seeds. Birds with bigger beaks could crack and eat seeds of all sizes. As a result, many of the small-beaked birds died in the drought. Birds with bigger beaks survived and reproduced (see Figure below ). Within 2 years, the average beak size in the finch population increased. Evolution by natural selection had occurred. and the situation: Two islands inhabited by many species of finches went through some climatic changes during the past several years. While Park island hat wetter than average years, Boat island experienced years of drought, so many birds died. Answer the following question: Which island had more large-beaked birds survive?
Ans: Boat

Given the background: Carbon dioxide is the most significant long-lived greenhouse gas in Earth's atmosphere. Since the Industrial Revolution anthropogenic emissions primarily from use of fossil fuels and deforestation have rapidly increased its concentration in the atmosphere, leading to global warming. Carbon dioxide also causes ocean acidification because it dissolves in water to form carbonic acid. and the situation: Two counties were part of the same region. Green county used alternative methods to produce energy, while Brown county used fossil fuels and released a lot of carbon dioxide into the atmosphere. Answer the following question: Which county caused more deforestation?
Ans: Brown