I read this background article the other day: The epidermis also contains melanocytes , which are cells that produce melanin. Melanin is the brownish pigment that gives skin much of its color. Everyone has about the same number of melanocytes, but the melanocytes of people with darker skin produce more melanin. The amount of melanin produced is determined by heredity and exposure to UV light, which increases melanin output. Exposure to UV light also stimulates the skin to produce vitamin D . Because melanin blocks UV light from penetrating the skin, people with darker skin may be at greater risk of vitamin D deficiency.  I am facing a new situation today: Matt and his brother Jesse are twins. They look almost identical. If it weren't for the fact that Jesse has a slightly darker skin complexion you wouldn't be able to tell them apart. In fact one year Matt was out in the sun for a long time and picked up a bit of a tan so they actually did look exactly alike.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Will the risk of a vitamin D deficiency increase or decrease when you skin is darker?
Ans: increase

I read this background article the other day: If a solution has a higher concentration of hydronium ions than pure water, it has a pH lower than 7. A solution with a pH lower than 7 is called an acid . As the hydronium ion concentration increases, the pH value decreases. Therefore, the more acidic a solution is, the lower its pH value is. Did you ever taste vinegar? Like other acids, it tastes sour. Stronger acids can be harmful to organisms. For example, stomach acid would eat through the stomach if it were not lined with a layer of mucus. Strong acids can also damage materials, even hard materials such as glass.  I am facing a new situation today: Alexiev and Sabrina were enthusiastic chemistry students completing the first experiment of their new course. They both started the experiment with pure water, and had to perform different experimental protocols to make changes to the water. At the end of the experiment, both of them measured the concentration of hydronium ions present in their reaction mixtures. Alexiev had a high concentration of hydronium ions present, while Sabrina had a low concentration present in her mixture.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which person's mixture, Alexiev's or Sabrina's, would be less harmful if swallowed?
Ans: Sabrina's

I read this background article the other day: Some individuals have a specific mutation in the primary sequence of their hemoglobin molecules that causes them to aggregate, resulting in a deformation of their red blood cells. This abnormality is genetic in nature. A person may inherit the gene from one parent and have sickle cell trait (only some of the hemoglobin is hemoglobin S), which is usually not life-threatening. Inheriting the gene from both parents will result in sickle cell disease, which is a very serious condition.  I am facing a new situation today: Doctors studied two groups of patients. Group W which had people with sickle cell disease, and group A which had normal people in it.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which group had fewer individuals with genetic abnormalities?
Ans: group A

I read this background article the other day: 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.  I am facing a new situation today: Joe lived in East Antarctica while his buddy Jim lived in West Antarctica. They were both into collecting rare specimens of plants and wildlife.  They would often complain about the weather.  Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which friend lived at a higher elevation?
