Question

CPC.
2. A pond weed was placed in a test tube containing pond
water and was exposed to bright sunlight. Bubbles
evolved at the cut end of the stem as shown in the figure.
In dim light and in darkness, no bubbles evolved.
Bubbles
Bright light
Pond weed
Pond water
(a) Name the gas that evolved in bright light.
(b) What is the process in which this gas has evolved?
(c) Why did the bubbles stop when there was still some
light falling on the plant?
(d) Gas is still being produced. Give one reason why gas
bubbles are not evolved in the darkness.​

Answer 1

Answer:

a.oxygen

b. photosynthesis

c. since there was no adequate light to occur photosynthesis

d. to occur photosynthesis we need light and the H2O break from PS2 reaction centre and O2 is liberated since there is no light so there will be no breaking of H2O and Oxygen will not be liberated