Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

[EX Q]: Question: The joints of the carpal bones in the wrist are examples of what type of joints? Answer: planar joints
[EX A]: Figure 38.27 The joints of the carpal bones in the wrist are examples of planar joints. (credit: modification of work by Brian C. Goss).

[EX Q]: Question: The mechanical advantage of a machine is related to how it changes what? Answer: force
[EX A]: The mechanical advantage of a machine is related to how it changes force. Explain this relationship.

[EX Q]: Question: How many additional pairs of appendages do arachnids have? Answer: 2
[EX A]:
Arachnids also have two additional pairs of appendages. Describe these two pairs.

