What technique uses a co-contraction of global muscles to enhance global trunk stability?

This technique is called ‘bracing’. The global muscles that are co-contracted are the rectus abdominis, external obliques and quadratus lumborum. This technique increases the muscular endurance of the global and local core muscles. The main advantage of this technique is that the increase in endurance of the global muscles act to stabilise the spine.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.

the answer is definitely a