What type of chemical bonds connects the complementary strands of a DNA molecule to each other?  

Which macro-molecule has a sugar-phosphate backbone?  

According to Emily Balcetis, softball players who’ve just come out of a slump see the ball as _______ and dieters see an apple as __________

Your mood gets more positive after working out because you experience

Emily Balcetis suggests that most Americans find their New Year’s Eve resolutions are broken by

When you investigate a newly discovered DNA polymerase from a deep sea microbe and you find that it has an error rate of 1 mistake in every 106  bases copied. However, the overall mutation rate is much lower. This is most likely because:

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1.2 Water pollution can occur if sewage enters a river. Explain the biological consequences of sewage pollution on a river ecosystem. (6)

3.1 What is meant by the term ecosystem (line 3)?   (2)

Pollution can occur in the atmosphere and in rivers. Carbon monoxide can pollute the atmosphere.   1.1 Describe the effects of carbon monoxide pollution on humans.   (3)