Pg.no. 147
36. Did you know?
1. Do you know that brain need continues supply of oxygen for better functioning?
2. Brain loses the ability of functioning, if it does not get oxygen for more than 4 min.
3. Do you know that sleeping enough and eating healthy food increase the efficiency of our
brain?
4. Don’t cover you face during sleep.
5. Aryabhatta, one of the great astronomers of ancient India was the first to say that the Earth
is round and rotates around its axis. At the young age 23 he wrote book on astronomy called
Aryabhatiya.
6. India has a great variety of fauna numbering 81,251. Species, which represent 6.67% of
the world’s fauna of these,
Insects – 60,000
Mollusca – 5,000
Birds – 1,228
Mammals – 372
Reptiles – 446
Amphibians – 204
Fishes – 2,546
7. India has a large variety of plants about 45,000 species in number of these,
Flowering plants – 15,000
Algae – 1,676
Lichens – 1,940
Fungi – 12,480
Gymnosperms – 64*
Bryophytes – 2,843
Pteridophytes – 1,012
8. The human body contains nearly 100 trillion cells.
9. There are at least 10 times as many bacteria in the human body as cells.
10. The average adult takes over 20,000 breaths a day.
11. Each day, the kidneys process about 200 quarts (50 gallons) of blood to filter out about 2
quarts of waste and water