Consider statements about evolution: 1. Natural selection was proposed by Darwin. 2. Evolution always leads to perfect organisms. 3. Homologous organs indicate common ancestry. Which are correct? MCQ with Answer and Explanation
Consider statements about evolution: 1. Natural selection was proposed by Darwin. 2. Evolution always leads to perfect organisms. 3. Homologous organs indicate common ancestry. Which are correct?
A. 1 and 2 only
B. 1, 2 and 3
C. 2 and 3 only
D. 1 and 3 only
Answer: Option D
Solution (By JKSSB Mock Tests)
Charles Darwin proposed the theory of evolution by natural selection, where organisms with favorable traits survive and reproduce. Homologous organs share a common structural plan and evolutionary origin, indicating divergent evolution from a common ancestor. Evolution does not lead to perfection; it only results in adaptation to the current environment. Thus, statements 1 and 3 are correct.
Explanation:
The QRS complex in an ECG represents the depolarization of the ventricles, which initiates ventricular contraction (systole). The P wave represents atrial depolarization. The T wave represents ventricular repolarization, which leads to ventricular relaxation (diastole). Atrial repolarization is usually masked by the larger QRS complex. Exam tip: P = atrial depolarization; QRS = ventricular depolarization; T = ventricular repolarization.
Explanation:
John Gibbon developed the heart-lung machine and performed the first successful open-heart surgery using it in 1953. Barnard did first heart transplant.
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