Do u know how to draw with india ink

Which of the following is an example of the endocrine system maintaining homeostasis? detecting a pain stimulus and sending a signal to the spinal cord to perform an automatic response discharging an excessive amount of hormones in the blood and not sending a signal to stop production releasing hormones that speed up heart rate and blood pressure while slowing body functions like digestion and growth using sense organs to get information about the outside world and direct an appropriate body response release

What are the colors that cannot be made by mixing other colors

To create an illustration of perspective, this artist did all of the following except 1) show clear orthogonal lines 2) have an implied vanishing point 3) distort proportion to keep the background and foreground the same size 4) include value changes between the foreground and background i was thinking maybe 1