In humans, having freckles is dominant over not having freckles. A heterozygous male with freckles has children with a female who does not have freckles. What fraction/percent of the children will not have freckles?

50%

Explanation:

If you do out the punnet square Ffxff, the result will be 50% of offspring with heterozygous (dominant trait is shown) and 50% will be homozygous recessive

your best option is 5,000 kg

a. by using fur or clothes to trap heat energy near the body