Multiple choice Which of the following pairs represents one and the same thing? Atrio-ventricular node − Pacemaker Corpus luteum − Yellow body Factor X − Thromboplastin Factor Mitral valve − Tricuspid valve Reveal answer Fill a bubble to check yourself B Correct answer Explanation The corpus luteum is a temporary endocrine structure formed in the ovary after ovulation, often referred to as the yellow body due to its appearance.