Question: Problem: I can use this background: Water stratification is when water masses with different properties - salinity (halocline), oxygenation (chemocline), density (pycnocline), temperature (thermocline) - form layers that act as barriers to water mixing which could lead to anoxia or euxinia.[1] These layers are normally arranged according to density, with the least dense water masses sitting above the more dense layers.  Water stratification also creates barriers to nutrient mixing between layers. This can affect the primary production in an area by limiting photosynthetic processes. When nutrients from the benthos cannot travel up into the photic zone, phytoplankton may be limited by nutrient availability. Lower primary production also leads to lower net productivity in waters.[2]  Now, I have a new situation: The marine biologists studied two areas of the Black Sea. Area A, situated at the mouth of the Danube River, which presented high levels of water stratification, because of the fresh water discharged by the river; and area B, situated 35 miles south, where the water was less stratified and more oxygenated.  Answer this question please: Which of the two areas has lower net productivity?

A: Area A


Problem: I can use this background: If only 1.0 mL of 0.10 M hydrochloric acid is added to 1.0 L of pure water the pH drops drastically from 7.0 to 4.0. This is a 1000-fold increase in the acidity of the solution. For many purposes, it is desirable to have a solution which is capable of resisting such large changes in pH when relatively small amounts of acid or base are added to them. Such a solution is called a buffer. A buffer is a solution of a weak acid or a base and its salt. Both components must be present for the system to act as a buffer to resist changes in pH. Commercial buffer solutions, which have a wide variety of pH values, can be obtained.  Now, I have a new situation: John is a scientist in a large pharmaceutical company. He devices many useful products using his knowledge of chemistry. Today, he has four solutions in front of him, solution A, solution B, solution C, and solution D. Solution A is a buffer, but solution B is not a buffer. Solution C is acidic, but solution D is not acidic. He needs to figure out what each solution does.  Answer this question please: Would solution A resist or assist in changes in pH?

A: resist


Problem: I can use this background: Fish reproduce sexually. They lay eggs that can be fertilized either inside or outside of the body. In most fish, the eggs develop outside of the mother's body. In the majority of these species, fertilization also takes place outside the mother's body. The male and female fish release their gametes into the surrounding water, where fertilization occurs. Female fish release very high numbers of eggs to increase the chances of fertilization.  Now, I have a new situation: Two neighboring ponds were stocked with adult fish last year. Hill pond had a very nice winter and the fish started reproducing normally, while Mound pond had no fish reproducing this spring.  Answer this question please: Which pond had more female fish release very high numbers of eggs?

A: Hill


Problem: I can use this background: Unfortunately, the layer of good ozone is being destroyed by air pollution. The chief culprits are chlorine and bromine gases. They are released in aerosol sprays, coolants, and other products. Loss of ozone has created an ozone hole over Antarctica. Ozone depletion results in higher levels of UV radiation reaching Earth. In humans, this increases skin cancers and eye cataracts. It also disturbs the nitrogen cycle, kills plankton, and disrupts ocean food webs. The total loss of the ozone layer would be devastating to most life. It’s rate of loss has slowed with restrictions on pollutants, but it is still at risk.  Now, I have a new situation: The researches studied the atmosphere in Antarctica, and close to Greenland. They found out there's an ozone hole over Antarctica.  Answer this question please: Which landmass had its atmosphere destroyed by chlorine gasses?

A:
Answer: Antarctica