"Null,infinite.finite or unit set. 1.the set of red cows.2.the set of lines which are perpendicular to the x-axis.3.the of natural numbers

"Null,infinite.finite or unit set. 1.the set of red cows.2.the set of lines which are perpendicular to the x-axis.3.the of natural numbers less than 13.4.the set of grade 7 teachers.5.the set of two digit numbers divisible by 3.​"