Why would eardrum affect one's ability to hear?

When studying heredity, what is the relationship of dna based and traits? super urgent !

Which description best defines the nervous system and its two main branches? a: the message center of the body, split into the autonomic nervous system and the somatic nervous system b: the control panel of the body, split into the central nervous system and the exterior nervous system c: the message center of the body, split into the central nervous system and the peripheral nervous system d: the control panel of the body, split into the brain and the spinal cord

Which of the following defines scoliosis? a. a posture disorder characterized by the shoulders being rounded and the back hunched b. a posture disorder in which the spine curves up the back like a snake c. a posture disorder characterized by excessive curvature or arch in the lower back d. none of the above