1.The circadian clock is
-a special mechanic clock.
-a daily cycle of activity observed in many living organisms.
2.Circadian rhythms
-are controlled by the clock.
-are controlled by the brain.
3.Today people can
-brighten the darkness.
-control their inner clock with medicines.
4.City residents can't see stars
-because of the air pollution.
-because the night lights are too bright.
5.Light pollution
-influences human health.
-is not a real problem.
6.Artificial light
-is very hazardous for human eyesight.
-doesn't hurt our sight.
7.Sunlight
-damages our eyes because of the UV.
-is less harmful than artificial light.
8.Melatonin is
-a hormone.
-a medicine for insomnia.
9.Staying awake at night
-is safe when you use enough light.
-influences our natural inner rhythms.
1. A daily cycle of activity observed in many living organisms
2. Are controlled by the brain
3. Brighten the darkness
4. Because the night lights are too bright
5. Influences human health
6. Doesn't hurt our sight
7. Damages our eyes because of the UV
8. A hormone
9. Influences our natural inner rhythms