Variant 1 You could have come first and won the race if you … faster

25. According to the passage ...

A) native insects and animals kill weeds and pests. B) the chemicals ultimately cause serious soil loss.

C) the chemicals we use to grow food are both beneficial and harmful.

D) pesticides also support the wildlife in the region, and protect ecosystems and wildlife.

26. One can understand from the passage that fertilizers are used ...

A) only when the crops are overgrown by weeds. B) to replace the nutrients that crops have taken out of the soil. C) because they have almost no ill effect upon the environment. D) since they help to restore ecosystems.

Sleep researchers have found that people can make themselves wake up аt a given time simply by deciding to do so before they go to sleep. Scientists took two groups of volunteers and at nightfall, told one group that they would be woken at 6 a.m. and the other that they would be woken at 9 a.m. The sleepers' levels of the hormone adrenocorticotropin, which is known to cause spontaneous awakening, were then measured. In each group, there was a rise in the levels of the hormone one hour before the 8 volunteers expected to get up. The three-hour difference between the rise in hormones in the two groups suggests that the body can be programmed to wake up on command.