Question

Dynamic stretches are part of an effective warm-up because they can help...

Lubricate muscles in the activity

Decrease cardiovascular difficulty in the activity

Expand lung capacity in the lung activity

build endurance for the activity

Answer 1

Dynamic stretches are part of an effective warm-up because they can help... 
lubricate the muscles used in the activity

Answer 2

Answer:

Option A, Lubricate muscles in the activity

Explanation:

Muscles become flexible during dynamic exercise. During such exercises the temperature of body increases which enhances  the flow of blood through the muscles and hence provide oxygen and glucose to muscles. Dynamic exercise provides the large amount of energy which is required by muscles in the start of any exercise/activity.  This also activates the muscles and increases the range of motion.

Hence, option A is correct