Tell me what is Huygens Principle with diagram (4marks question) please don't copy or spam​

The particles of an ice cube at 0°c (represented by the blue circles) come in contact with the particles of juan’s hand at 37°c (represented by the orange circles). which diagram correctly represents the temperature of the two substances and the direction of heat flow?

Determine the maximum r-value of the polar equation r =3+3 cos 0

If angle "a" is 25°, angle "b" is: a) equal to angle c b) less than angle c c) greater than angle c