Blackman's law of limiting factors says that

Question

Accepted Answer

D. the rate is set by whichever factor is in shortest supply

Blackman (1905) formalised the bottleneck principle: a multi-input process runs at the rate of its slowest-supplied input.
Doubling other inputs has no effect until the limiting factor changes.
Once you increase the limiting one, the new limit shifts to whichever is now the bottleneck.

Answer

every factor must be at maximum simultaneously

Answer

doubling any one factor doubles the rate regardless of others

Answer

plants ignore CO₂ if temperature is below freezing

Blackman's law of limiting factors says that

Keep practising Photosynthesis in Higher Plants