Answer: The small size and poor accessibility of the nervous system in the blackworm are barriers to elucidating the control of peristalsis; however, the transparent cuticle, the large size of the dorsal blood vessel (DVB), and the red-pigmented blood allow for non-invasive methods of observation that can yield indirect evidence to help explain these mechanisms
Explanation: Studying the nervous system advances understanding of our basic biology and body function. Knowing how things typically work can help shed light on what may happen when there are problems.
