When you swallow food, it doesn't just drop down into your stomach. Muscles contract in a wave-like motion to move the food along through the esophagus. This muscle movement is called, peristalsis, or peristaltic waves. These peristaltic waves contract behind the food bolus pushing it along the digestive tract.
Nope, because they serve no purpose on earth
Answer:
B. interconnected
Explanation:
All the systems in our bodies (humans are indeed animals) are connected with each other to create a functional being. The blood flows throughout the body, providing nutrients; the bones support the structure and protect the heart and lungs. They work together.
Why not A: The systems are all completely necessary. There's nothing extraneous in our bodies, because extraneous stuff takes up energy, and our biology is incredibly economical.
Why not B: They're not interchangeable. How would you like your bones to turn to blood? Uh-huh.
Why not D: They interact with each other consistently, so they're not separate or segregated.
Explanation:
Receptors = Sensory neurons
Relay = Relay neurons
Effectors = Motor neurons
Cell bodies of sensory neurons are only found in the root ganglion. (F)
Cell bodies of relay neurons are only found is the grey matter of the spinal cord. (G)
Cell bodies of motor neurons are also found at G.
Hence the answer is Option D.
Answer:
Ptolemy included epicycles in his orbits.
Explanation:
Ptolomy's model of the solar system was geocentric, where the sun, moon, planets, and stars all orbit the earth in perfectly circular orbits. The problem with perfectly circular orbit around the Earth is that they do not explain the occasional backward motion, or retrograde motion, of the planets.
The Greeks insisted that the motion of the planets be perfectly circular. Ptolemy modeled the planets making small circles around a point that orbited the Earth. These smaller circles were called epicycles, and they allowed the planets to move backward relative to the background stars.
