which hypothesis best predicts how a change to the gene affect people who do not produce enough lactase

Since a female is both xx chromosome and the male passes down the x chromosome, than the offspring would be female since a female is xx.

We also sweat while we exercise. while we exercise, we do burn glucose and in the process generate the energy we need. that energy also causes us to heat up and as part of our temperature regulation mechanism, we sweat to get rid of the excess heat. and that water that we sweat has a fairly large amount of mass which we then lose.