Question

why do some substances absorb heat radiation while others reflect or refract?

Answer 1

Dear Student

Heat is a mode of transfer of energy from a body (or surroundings) a higher temperature to a body (or surroundings) at lower temperature.
So, it depends on the temperature difference. Now, from the question, it looks like you are asking about heat exchange at NTP conditions (Temp = 20°C = 293.15K). Those substances having less temperature than this will absorb heat while those with more, will radiate.

Regards