Problem: I can use this background: One of the most common chromosome abnormalities is Down syndrome , due to nondisjunction of chromosome 21 resulting in an extra complete chromosome 21, or part of chromosome 21 ( Figure below ). Down syndrome is the only autosomal trisomy where an affected individual may survive to adulthood. Individuals with Down syndrome often have some degree of mental retardation, some impairment of physical growth, and a specific facial appearance. With proper assistance, individuals with Down syndrome can become successful, contributing members of society. The incidence of Down syndrome increases with maternal age. The risk of having a child with Down syndrome is significantly higher among women age 35 and older.  Now, I have a new situation: Mary had two children. Her firs born was named Bill and was normal, and her second child was named Sam and had Down syndrome.  Answer this question please: Which child had an autosomal trisomy ?

A: Sam


Problem: I can use this background: Enzymes increase the rate of chemical reactions by reducing the amount of activation energy needed for reactants to start reacting. One way this can happen is modeled in the Figure below . Enzymes aren’t changed or used up in the reactions they catalyze, so they can be used to speed up the same reaction over and over again. Each enzyme is highly specific for the particular reaction is catalyzes, so enzymes are very effective. A reaction that would take many years to occur without its enzyme might occur in a split second with the enzyme. Enzymes are also very efficient, so waste products rarely form.  Now, I have a new situation: David is a chemist, working for a large pharmaceutical company. He was contemplating on a project that would help perform chemical reactions more efficiently. For that, he conducted two chemical reaction tests, test A and test B. In test A he used enzymes, but in test B he didn't use any enzymes. He now needs to evaluate the  pros and cons of each of the tests.  Answer this question please: Which test would require more activation energy, test A or test B?

A: test B


Problem: I can use this background: Rain dissolves fertilizer in the soil. Runoff carries it away. The fertilizer ends up in bodies of water, from ponds to oceans. Nitrogen is a fertilizer in the water. Since there is a lot of nitrogen, it causes algae to grow out of control. Pictured below is a pond covered with algae ( Figure below ). Algae use up carbon dioxide in the water. After the algae die, decomposers break down the dead tissue. The decomposers use up all the oxygen in the water. This creates a dead zone. A dead zone is an area in a body of water where nothing grows because there is too little oxygen. There is a large dead zone in the Gulf of Mexico ( Figure below ). The U.S. states outlined on the map have rivers that drain into the Gulf of Mexico. The rivers drain vast agricultural lands. The water carries fertilizer from these areas into the Gulf.  Now, I have a new situation: Jim and Greg are brothers who both run their own farms, but they rarely see each other due to them living in different states. Greg runs a farm in Texas where he rarely sees rain so he spends much of his day watering his crops. Jim lives in Illinois where it rains much more regularly so he has more time to spend dealing with his farm animals instead of watering his plants. Both men intentionally purchased their farms next to lakes since they have always loved fishing during their free time. The brothers are currently planning a fishing trip together, but they are just debating which lake to travel to.  Answer this question please: Whose lake will have more nitrogen in it?

A: Jim


Problem: I can use this background: In grassland, much of the organic matter added to the soil is from the deep, fibrous, grass root systems. By contrast, tree leaves falling on the forest floor are the principal source of soil organic matter in the forest. Another difference is the frequent occurrence in the grasslands of fires that destroy large amounts of aboveground material but stimulate even greater contributions from roots. Also, the much greater acidity under any forests inhibits the action of certain soil organisms that otherwise would mix much of the surface litter into the mineral soil. As a result, the soils under grasslands generally develop a thicker A horizon with a deeper distribution of organic matter than in comparable soils under forests, which characteristically store most of their organic matter in the forest floor (O horizon) and thin A horizon.  Now, I have a new situation: Kim and Jane inherited some land. Kim inherited some grassland, while Jane inherited a forest. They both took good care of their properties.  Answer this question please: Which person inherited a parcel where leaves are not the principal source of soil organic matter?

A: