In: Biology
1. Which of the following statements about the world’s population is FALSE?
a. the rate of population growth has increased since the end of the twentieth century |
b. urbanization is taking place in developed, developing, and non-developed countries |
c. more people live in urban areas than in rural areas 2. Scientists want to know what effects, if any, there might be from increasing levels of UV-B radiation due to the stratospheric ozone hole. In an experiment to study the effects of above-normal UV-B radiation on leopard frogs, treatment and controls included 10 frogs. This provided adequate _____________ so that any difference due to the treatment would not be due to ______________factors.
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1: The correct option is Option B - (urbanization is taking place in developed, developing, and non-developed countries)
Urbanization is taking place in developed and developing nations, and only to a small extent in non-developed nations.
The other two statements are true. More than 50% population lives in urban areas. Since the beginning of the century, population growth rates have been steadily increasing.
2. The correct option is Option B (replication; confounding)
Any experiment will have one control and several replicates. The purpose is to compare the effects of treatment on a sample, as compared to a sample that has not undergone any treatment. For statistical analysis, replicates are maintained to reduce any chances of error
3. The correct option is Option A (rowing algae mats shed dead material and these sediments cloud the water column and coat surfaces, which prevents aquatic plants from photosynthesizing.).
When algal cells die, they are decomposed by bacterial activity, which leads to an increase in the concentration of nutrients in the water bodies. Aerobic bacteria can feed on these nutrients and use up all oxygen. Since the algal mats prevent sunlight from reaching the water body floor, the plants at the bottom cannot photosynthesize, and the oxygen level of the water body further dips down.