Can someone do a dichotomous key for me?

Which of the following is a good strategy when it comes to desserts

Methane gas created by a cows flatulence especially in a large herd is a greenhouse gas. true or false.

Each member of a class sampled a piece of ptc testing paper. thirty people sampled the chemical. twenty persons were tasters. how many had heterozygous genes? 10 20 0-20 indeterminate