Practice question

Degradation of HY5 (B) is correct here. This is core cryptochrome: once you know the definition or pathway step, Degradation of HY5 is the clear fit. The wrong ones are A) Activation of HY5; C) Activation of cryptochrome; D) Inhibition of ubiquitination. If the topic is about gradients or potentials, water/solutes move from higher to lower of the relevant quantity.