Which of the following is/are important features of a weight system? The ability to quickly and reliably jettison at least enough weight to make the wearer positively buoyant at the surface or at depth. The ability to carry a minimum of at least 25 kg/55 lbs of weight. The ability to easily adjust the amount of weight used. Both the first and third answers are correct.

Both the first and the third answers are correct

Explanation:

Weighting systems are worn by divers to help balance the buoyant or upward thrust movement of the water on equipment such as the diving cylinders carried along with the diver during the dive,

A quick release mechanism can aid in the emergency rescue of a diver by dropping the weight to increase the diver's buoyancy so as to rapidly rise to the surface

The weighting system arrangement is such that part or all of the weight could be  removed to allow an immediate increase in the divers buoyancy

Therefore, both the first and the third answers are correct.