Registered nurses who return to school to further develop their professional skills and training and focus on a specific area such as anesthesia are called nurses.

A RN who returns to school to develop their knowledge and specifically focus on anesthesia are called CRNA's which stands for Certified Registered Nurse Anesthetist.

The answer is letter B.

Poor aerobic capacity can make it difficult to perform certain activities that involve aerobic threshold. Examples of these exercises are brisk walking for 30 minutes, running for 20-30 minutes, or playing badminton.

Aerobic capacity refers to the ability of the cardiorespiratory system to work together in synchronicity in able to supply the body with the enough oxygen it needs to perform muscle contractions. This process happens through the circulatory system when the blood flows from the heart to the lungs and into the different parts of the body. Having a poor aerobic capacity means that the cardiorespiratory and circulatory systems are not efficiently working together leading to poor performance in different activities.