The period during which an excitable membrane can respond again, but only if the stimulus is greater than the threshold stimulus, is the period.

The correct answer is - relative refractory period.

Explanation:

The relative refractory period is a period that stimulates a secondary response if the stimuli are greater than the normal. It occurs when partial repolarization after a nerve fiber fired.

The relative refractory period is one of the two types of the refractory period which is the relative and absolute refractory period. In the absolute refractory period, it is not possible to activate another action potential in membrane.

Thus, the correct answer is -  relative refractory period.

wild parsnip is a perennial plant which reproduces rapidly in areas which have no sign of agricultural activity such roadside or at no tillage open areas. it's considered invasive because it can inhibit the growth of another plant  and its reproduction is fast. there are several harmful effects of this invasive plant although its taproot is edible since it is a member of the carrot family. wild parsnips can cause skin blistering when in contact because of the chemicals it contains, second it inhibits the growth of other plants, it will restrict the growth of animals when eaten and lastly, it drives away natural pollinators like bees.