How does the EDA pathway affect the development of lateral plates?

• A. EDA signaling promotes the development of lateral plates; reduced signaling results in fewer plates.
• B. EDA signaling reduces the number of lateral plates.
• C. EDA pathway only affects fin shape, not plates.
• D. EDA signaling increases bone density but not plate number.

Answer: (A)

EDA signaling serves as a trigger that promotes the formation of lateral plates along the body. When this signaling is active, more plates develop; when signaling is reduced, fewer plates form. That means the statement that EDA signaling promotes plate development and that reduced signaling leads to fewer plates is the best description of how this pathway influences lateral plates. The other options miss this promotional role or describe effects that aren’t supported, such as only affecting fin shape or increasing bone density without changing plate number.