Please answer fast Many commercial herbicides act by inhibiting photosynthetic electron transport. They are investigating three herbicides for potential inhibitors of photosynthetic electron...

Please answer fast

Many commercial herbicides act by inhibiting photosynthetic electron transport. They are investigating three herbicides for potential inhibitors of photosynthetic electron transport.

a) How can you determine whether these substances have an inhibitory effect on photosynthetic electron transport? How can you quantify the effect?

b) An inhibitor has produced a strong effect in "in vitro" tests, but the effect is significantly less in "in vivo" tests. What can be the reason for the reduced effect "in vivo"?