When the reactions that occur in the body are made to happen in laboratory conditions they are said to be

The correct option is "Living reactions".

To understand why this is the correct classification, let us break down the concepts involved:
1. In Vivo vs. In Vitro: Reactions occurring inside a living body (in vivo) are part of its metabolism. When we isolate these reactions and perform them outside the body in a laboratory test tube (in vitro), they are no longer inside a living organism.
2. Nature of the Reactions: Although the test tube itself is non-living, the reactions being carried out are biological reactions that naturally occur in living systems. Because they mimic the exact processes of life, they are characterized as living reactions, even though they are occurring in a non-living environment.

Therefore, when reactions that occur inside the body are performed under laboratory conditions, they are said to be living reactions (specifically, living reactions occurring in a non-living environment).