Read the following statements: (1) The muscles of the heart are voluntary muscles. (2) The ear lobes and lips do not have bones. (3) The spinal cord along with the brain forms the main part of the nervous system. (4) The elbow and knee have ball and socket joint. Which of the above statements is/are incorrect?

Answer: C. Only 1 and 4

The muscles of the heart are involuntary muscles, not voluntary, so statement 1 is incorrect. The ear lobes and lips do not contain bones, so statement 2 is correct. The brain and spinal cord together form the central nervous system, so statement 3 is correct. The elbow and knee are hinge joints, not ball and socket joints, so statement 4 is incorrect. Therefore, statements 1 and 4 are incorrect.

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