Problem: Students learned about protozoa in school this week. Dan and Jim were interested and read more on the subject. Dan read more about predatory protozoa, while Jim read more about herbivore protozoa. Which student read less about protozoa preying upon single-celled organisms? Hint: Protozoa generally feed by engulfing and digesting other organisms. As consumers, they have various roles in food chains and webs. Some are predators. They prey upon other single-celled organisms, such as bacteria. In fact, protozoa predators keep many bacterial populations in check. Other protozoa are herbivores. They graze on algae. Still others are decomposers. They consume dead organic matter. There are also parasitic protozoa that live in or on living hosts. For example, the protozoan that causes malaria lives inside a human host. For their part, protozoa are important food sources for many larger organisms, including insects and worms.

A: Jim

Problem: Two scientists went to Antarctica for research. Tim was assigned to East Antarctica, while John was assigned to West Antarctica. They spent 6 months there. Which scientist was located at a higher elevation? Hint: East Antarctica is colder than its western counterpart because of its higher elevation. Weather fronts rarely penetrate far into the continent, leaving the centre cold and dry. Despite the lack of precipitation over the central portion of the continent, ice there lasts for extended periods. Heavy snowfalls are common on the coastal portion of the continent, where snowfalls of up to 1.22 metres (48 in) in 48 hours have been recorded.

A: Tim

Problem: Pat has 2 acres of land next to Tim's property. Tim's land is of similar size. The clay soil on Tim's property is very alkaline, so he had to amend it with aluminum salts to make it more acidic in order to grow crops. The soil on Pat's parcel has a good structure and high infiltration capacity. Pat gets twice as much food of his land every year. Which soil is more alkaline, the one on Pat's or the one on Tim's? Hint: Alkali, or Alkaline, soils are clay soils with high pH (> 8.5), a poor soil structure and a low infiltration capacity. Often they have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physico-chemical properties mainly to the dominating presence of sodium carbonate, which causes the soil to swell[1] and difficult to clarify/settle. They derive their name from the alkali metal group of elements, to which sodium belongs, and which can induce basicity. Sometimes these soils are also referred to as alkaline sodic soils. Alkaline soils are basic, but not all basic soils are alkaline.

A: Tim's

Problem: Rob is testing the properties of gas. To that end, he experimented with a cylinder of gas in three stages, stage A, stage B, and stage C. In stage A he kept the gas in room temperature. In stage B he heated the gas up. And in stage C he cooled the gas down. In which stage the gas molecules would collide more forcefully with the interior surface of the cylinder, stage A or stage B? Hint: Shown in the Figure below is a cylinder of gas on the left that is at room temperature (300 K). On the right, the cylinder has been heated until the Kelvin temperature has doubled to 600 K. The kinetic energy of the gas molecules increases, so collisions with the walls of the container are now more forceful than they were before. As a result, the pressure of the gas doubles. Decreasing the temperature would have the opposite effect, and the pressure of an enclosed gas would decrease.

A:
stage B