Question

*PLEASE ANSWER ASAP*
11.Which of the following is not a concave mirror?
a)dentist's mirror
b)shaving mirror
c)rear view mirror of bike
d)both a) and b)
12. chemical used to disinfect water
a) ozone
b)sugar
c) both a)and b)
d) silica
13.Which substance kill microbes that help purify water?
cooking oil
food remains
motor oil
used tealeaves
14. An organ that is not associated with the respiratory system of human being is
a) lungs
b) spiracles
c) nostrils
d) diaphragm
15. The end products of anaerobic respiration are
a) carbon dioxide + oxygen
b) carbon dioxide + hydrogen
c) alcohol + carbon dioxide
d) alcohol + oxygen
16. Seeds dispersed by animals have
a) fibrous covering
b) wings
c) hooks
d) none of these
17. A male reproductive part of flower which contain pollen grains
a) filament
b) anther
c) style
d) ovule
18.When an iron nail is dipped in copper sulphate solution for some hours
a) the solution turns blue to green
b) a brown layer is deposited on the nail
c) a chemical reaction takes place
d)all of these
19. crystallization is a
a) physical change
b)chemical change
c)irreversible change
d)none of these
20. spirogyra reproduces by
a) fragmentation
b) spore formation
c) budding
d) vegetative propagation

Answer 1

11)rear view mirror of bike

12)ozone

13)paints

14nostrils

15