What is the meaning of resistors?

Question

Arduino

I met an article on Habré about connecting a simple pump to Arduino:
habrahabr.ru/post/210814
But I'm quite far from electrical engineering, and I don't understand the purpose of the resistors in this circuit:

What is their purpose and why such a rating?
PS: At the same time, please clarify about the diode.
As I understand it, during a circuit break, the motor by inertia releases voltage, which can break through the transistor and damage the controller. So?

Answer 1

The 100 ohm resistor limits the gate current.
The 100 kΩ resistor pulls the gate to zero when the microcontroller output is disconnected or in the third state.
Diode - protection of the transistor from the self-induction current of the motor.

Answer 2

100 ohm protects the output of the microcontroller, if the transistor is broken
100 kΩ pulls it to zero (if you removed the microcontroller from the socket)
You understood correctly about the diode, when turned off, any inductance generates an EMF directed towards the current flow. Resp. the total voltage, supply + EMF can break through the transistor.