You are studying a plant whose seeds persist in the soil for a long time, normally only germinating when the seeds are brought to the surface in full sun by a disturbance such as a tree fall. However, in one of your experimental lineages you find that many seeds germinate when the surface is in full sun even if the seeds are buried too deep to grow to the surface before exhausting their reserves. You suspect that this lineage has a mutation that inhibits:

The conversion of Pfr to Pr.

Explanation:

If the seeds germinates properly  when the surface is in full sun and persist to germinate when buried deep into the soil, this shows that this lineage of seeds  has a mutation that inhibits the conversion of Pfr to Pr

is this a psat question, if so do not cheat try your best.

primary succession occurs in essentially lifeless areas regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. secondary succession occurs