What are the answers to the following questions about digital systems, algorithms, binary conversion, robotics, and expert systems?

Here are the answers to the questions:

6. C. 0 In digital systems, a bit that is "OFF" or at a low voltage level typically represents the binary value 0.

7. C. algorithm. An algorithm is a precise, step-by-step set of instructions or a formula for solving a problem or completing a task.

8. A. $1111_2$ To convert $15_{\text{ten}}$ to binary, we repeatedly divide by 2 and record the remainders:

   $$15 \div 2 = 7 \text{ remainder } 1$$ $$7 \div 2 = 3 \text{ remainder } 1$$ $$3 \div 2 = 1 \text{ remainder } 1$$ $$1 \div 2 = 0 \text{ remainder } 1$$

   Reading the remainders from bottom to top gives $1111_2$.

9. B. actuators. Actuators are components in a robot that convert electrical, hydraulic, or pneumatic energy into mechanical motion, enabling the robot to move and manipulate objects in its environment.

10. D. specifies a condition and an action to be taken. The IF-THEN control structure in an expert system is a rule that defines a relationship between a condition (the "IF" part) and a resulting action or conclusion (the "THEN" part).