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:

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

  Use only if needed

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

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)