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Materials are transported within a single-celled organism by the*
Which row in the chart below correctly pairs a food molecule with its building block?
The flow of energy in an ecosystem is best described as energy moving in*
Occasionally, during pregnancy, the placenta can separate from the uterus. This causes a disruption in development and sometimes death of the fetus. Harm to the developing fetus might occur because the placenta*
Which process produces only identical offspring?*
A photograph of human cells as seen with a compound light microscope is shown below. A cell structure is labeled A.
Structure A is most likely a*
A land-dwelling organism, A, and an aquatic single-celled organism, B, are represented below.
Which statement best explains how A and B are able to survive in their environments?*
A man is exposed to large amounts of ultraviolet radiation while sunbathing at the beach. This exposure causes a genetic change in the DNA of a skin cell. In the future, this change can be passed on to*
Palm oil, produced from palm trees, is not only a biofuel, but is also used in food additives, cosmetics, and lubricants. Palm tree plantations are now cultivated in areas that were formerly natural forests. One ecological concern raised by this expansion is that*
Fishermen have harvested certain fish to the point where the population of that fish is decreasing. This level of direct harvesting could cause*
Which phrase best describes a gene?*
The molecule DNA contains the four bases listed below.
A – adenine C – cytosine G – guanine T – thymine
Which base pairings normally occur during DNA replication?*
Evolution of a species could occur as a result of changes in the*
One positive impact that industrialization has had is that*
When receiving x rays, individuals wear a lead shield over major organs in order to limit the body’s exposure to radiation. One reason for this procedure is to*