Problem: An enzyme is a protein that acts as a biological catalyst. Recall that a catalyst is a substance that increases the rate of a chemical reaction without itself being consumed in the reaction. Cellular processes consist of many chemical reactions that must occur quickly in order for the cell to function properly. Enzymes catalyze most of the chemical reactions that occur in a cell. A substrate is the molecule or molecules on which the enzyme acts. In the urease catalyzed reaction above, urea is the substrate. The Figure below diagrams a typical enzymatic reaction. Robert is a scientist that is analyzing the skin cells he obtained from a new species of spider. He is comparing two cells side by side. He notices that the cell on the left, cell A, does not have any enzymes present. The cell on the right, cell B, however contains a large number of enzymes. Which cell will have faster chemical reactions?

A: cell B

Problem: 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. Two groups of patients were under observation for heart disease. The Red group was composed of people with low cholesterol, while the Yellow group was comprised of people with very high cholesterol. Which group had fewer people with lowered oxygen supply to the heart muscle?

A: Red

Problem: Ecologically, the expansion of drainage systems has had tremendous negative effects. Hundreds of thousands of wetland species experienced significant population declines as their habitat was increasingly fragmented and destroyed. Although market hunting within the Central Flyway was a contributing factor in the decline of many waterfowl species' numbers in the early decades of the twentieth century, loss of breeding habitat to agricultural expansion is certainly the most significant. Early maps of midwestern states depict many lakes and marshes that are either nonexistent or significantly reduced in area today. Channelization, a related process of concentrating and facilitating the flow of water from agricultural areas, also contributed to this degradation. Timber village started a channelization process by draining all the swamps near their village. Hill village situated 10 miles to the south, left their swamps untouched. Which village drained more swamps situated in their vicinity?

A: Timber

Problem: In the natural world, ants of some species (initially) wander randomly, and upon finding food return to their colony while laying down pheromone trails. If other ants find such a path, they are likely not to keep travelling at random, but instead to follow the trail, returning and reinforcing it if they eventually find food (see Ant communication). Over time, however, the pheromone trail starts to evaporate, thus reducing its attractive strength. The more time it takes for an ant to travel down the path and back again, the more time the pheromones have to evaporate. A short path, by comparison, gets marched over more frequently, and thus the pheromone density becomes higher on shorter paths than longer ones. Pheromone evaporation also has the advantage of avoiding the convergence to a locally optimal solution. If there were no evaporation at all, the paths chosen by the first ants would tend to be excessively attractive to the following ones. In that case, the exploration of the solution space would be constrained. The influence of pheromone evaporation in real ant systems is unclear, but it is very important in artificial systems.[8] Ricky, an entomologist, is observing an ant colony in his back yard. After some observation, he discovers that all the ants travel down one of two distinct paths in order to find food to bring back to the colony. After taking some measurements, Ricky sees that path A is approximately 100 meters in length, and path B is approximately 150 meters in length. Ricky is now trying to make some scientific conclusions based on these observations. Which path will be marched over more frequently?

A:
path A