A lymphatic organ that helps develop the immune system is the thymus gland. The main function of this soft, roughly triangular organ is training and development of T-lymphocytes or T cells, an extremely important type of white blood cell which defend the body from potentially deadly pathogens such as bacteria, viruses, and fungi. Correct answer: B
The answer is D, since you are keeping your back straight. Your back will curve forward with poor posture.
