Why is it sometimes necessary to conserve a plant species ex situ?

This question is all about conservation. While many students dislike ecology because it may seem a bit wishy-washy and not really "proper science", it is actually very important as we need to understand our relationships with other species to prevent degradation of our environemnt which has led to many species' extinction.There are many very good answers to this question. Conserving a plant species "ex situ" simply means outside its natural environment. Reasons you could give for this may include: their natural habitat has been lost due to human activities (e.g. deforestation), the population of the plant species is at a dangerously low level, ex situ allows protection from predators and disease, and so on.It is useful to learn a few simple reasons like this so in the exam you can just easily write them down.