Q: 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. Paragraph: Norm and Ian were two brothers. Norm was a totally normal individual, while Ian had Down syndrome. Their parents loved them both equally. Given the paragraph above, please answer correctly the following question: Which brother had a nondisjunction of chromosome 21?
A: Ian

Q: Background: Leucism (/luszm, -kz-/)[1][2][3] is a condition in which there is partial loss of pigmentation in an animal resulting in white, pale, or patchy coloration of the skin, hair, feathers, scales or cuticle, but not the eyes.[3] It is occasionally spelled leukism. Unlike albinism, it is caused by a reduction in multiple types of pigment, not just melanin. Paragraph: There is a strange phenomenon going on in Siberia. Biologist noticed that 60 percent of the Siberian Tigers have leucism, and another 40 percent have albinism. They labeled the first group as group A and the latter one as group B. They need to find the reasons for this phenomenon. Given the paragraph above, please answer correctly the following question: Eyes not affected by loss of pigmentation is an important characteristic of which group, group A or group B?
A: group A

Q: Background: One result of air pollution is acid rain. Acid rain is precipitation with a low (acidic) pH. This rain can be very destructive to wildlife. When acid rain falls in forests, freshwater habitats, or soils, it can kill insects and aquatic life. It causes this damage because of its very low pH. Sulfur oxides and nitrogen oxides in the air both cause acid rain to form ( Figure below ). Sulfur oxides are chemicals that are released from coal-fired power plants. Nitrogen oxides are released from motor vehicle exhaust. Paragraph: Hydrologists studied two samples of rain water. Jim studied an acid rain sample from a nearby city, and Dan studied a sample of water from another town. Given the paragraph above, please answer correctly the following question: Which hydrologist learned less about the causes of acid rain formation?
A: Dan

Q: Background: Gasoline-powered vehicles emit a lot of harmful materials. Nitrogen oxides are formed when atmospheric nitrogen reacts with oxygen at the high temperatures found in a car engine. Carbon monoxide is a by-product of incomplete combustion of hydrocarbons. Evaporated and unused fuel releases volatile hydrocarbons into the atmosphere to help form smog. The presence of a catalytic converter in the exhaust system of the car causes these materials to react and be changed into less harmful products. Paragraph: After decades of debate, Brunei decided to adopt electrical vehicles and use them extensively, ultimately phasing out gasoline powered vehicles. Their neighbor Nepal decided to continue using gasoline-powered vehicles extensively. Given the paragraph above, please answer correctly the following question: Which country experienced more volatile hydrocarbons in the atmosphere?
A:
Nepal