Question

You have an Elodea sprig in a test tube containing bromothymol blue. Then you watch it for several days. At what time of day will the oxygen level in the tube be the lowest?
a)just before sunset
b)midnight
c)just before sunrise
d)mid-afternoon

Answer 1

Answer:

The correct answer is - option A) just before sunset

Explanation:

The elodea spring is like any other plant that gets its energy through photosynthesis by utilizing light, carbon dioxide, and water. When it is placed in a test tube with water and bromothymol blue and observe the concentration of oxygen.

In the time of day where it will get light, it will show a higher dissolved Oxygen value as it is a photosynthesis by-product and during the time of day when there is no light or dark period dissolved oxygen will be lowest as the photosynthesis process did not occur and in dark plants shows respiration which uses oxygen.