This question was unpopular and poorly attempted. Candidates merely stated the effect of temperature on surface tension without explanation as demanded by the question.  Candidates failed to interpret correctly between the demands of question framed with “What is the effect” “explain “the effect”.

The expected answer is:

The higher/lower the temperature of a liquid the lower/higher its surface tension. 

This is because at higher/lower temperatures the molecules, including those at the surface, have gained/lost more energy and become more/less mobile thereby decreasing/increasing the forces at the liquid surface.