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The activity of a single-celled organism is represented in the diagram below.
Which concept is best illustrated by this diagram?*
The chart below shows a comparison of the blood sugar levels for two individuals who took part in a scientific study.
Scientists have observed that blood sugar levels rose by different amounts in the two individuals even though they were given identical portions of bananas and cookies. These results were obtained because*
Plants are green because they contain the protein chlorophyll. A bucket was left on the lawn for one week. When the bucket was removed, the grass under the bucket had turned from green to a yellowish white color. This change is due to the interaction between the grass and*
In the summer, the arctic fox appears brown because its cells produce a dark pigment. However, in the winter, the arctic fox appears white because the dark pigment is not produced. The color change is most likely due to the effect of*
Researchers recently discovered that when hammerhead sharks were moved to shallower water, resulting in exposure to increased light intensity, their backs turned a deep brownish black. Which statement best supports this observation?*
A hydrangea plant has blue flowers when grown in acidic soil, but has pink flowers when grown in basic soil. A clone of the pink-flowered plant is grown in acidic soil and produces blue flowers. This change in flower color is most likely due to*
The photographs below are of two Siamese cats.
The Siamese breed has a gene that controls fur color. The cat in the first photograph was kept indoors while the cat in the second photograph was kept outdoors. Which statement best explains the differences in fur color between these two cats?*
A photograph of a Siamese cat is shown below.
Siamese cats have dark fur on areas of the body that are cooler and light fur on parts of the body that are warmer. The color differences in this Siamese cat are most likely due to*
Identical twins were separated at birth and raised by two different families. Years later, one twin was a physically fit member of the cross-country team, and the other twin was overweight with slightly higher-than-normal blood pressure. The differences in these twins could be explained by the fact that*
The diagram below represents genetic material.
The expression of the section labeled X may be modified by*
Chlorophyll gives plants their green color. Chlorophyll is produced only when plants are exposed to light, so plants kept in darkness have no chlorophyll and appear white. The best explanation for this is that*
Base your answers to questions 12 on the passage below and on your knowledge of biology. Biologists have been studying the genes present in newborn twins.
Twins Don’t Share Everything
…Chemicals called epigenetic markers can be attached to those [inherited] genes, like flags or balloons hanging off the sides of the DNA ladder. These don’t just change the look of the genes. Like pieces of tape stuck over a light switch, these markers can force a gene to remain turned on or off. The type of marker scientists studied in the twins generally sticks the switch in the off position so that some proteins don’t get made. And that means the proteins’ jobs won’t get done.
Every time a cell divides, new epigenetic markers may form. Foods, pollutants, and stress may all contribute to the development of new markers. So throughout our lives we tend to accumulate more and more. But a few are there from the day we’re born.
…His [Jeffrey Craig’s] team found that newborn twins have markers attached to different genes from the very start. It’s true in identical twins, which come from the same fertilized egg. It’s also true in fraternal twins, which come from different fertilized eggs. However, fraternal twins had more such differences than identical twins did.
Source: Science News for Students; July 31, 2012
Identify two environmental factors that can lead to an increase in the number of epigenetic markers that modify gene expression. *
Base your answer to question 13-17 on the information below and on your knowledge of biology.
New varieties of organisms have resulted from human activities. These organisms have often led to problems in modern society. Two of these new varieties are listed below.
Antibiotic-resistant bacteria Pesticide-resistant insects
Select one of these varieties and discuss a problem associated with the development of this new variety of organism. In your answer, be sure to:
• identify the variety you selected
• identify one biological process by which a population of this variety may develop resistance 
• describe how this process is involved in the production of a population of resistant organisms 
• identify one problem caused by this resistance 
• state one solution to this problem 
• identify one possible negative effect of this solution 
For many years, health officials had encouraged using antibacterial hand soap. Today, many scientists recommend using hand soap with no added antibacterial substances. State one reason why using antibacterial hand soap may no longer be recommended. *
Base your answers to questions 19 on the information below and on your knowledge of biology.
EVOLUTION OF THE ELEPHANT
Today’s elephants are the result of a long process of evolution. Over millions of years, small changes were passed from one generation to the next. The first fossil elephant species were small, but over time, they increased both in size and weight. The three species alive today are the sole survivors of a once much more widespread group.
Explain why some elephant species did not survive. *