Which of the following are sets? Justify your answer.
The collection of all even integers.

Which of the following are sets ? Justify your answer. The collection of all natural numbers less than 100.

Which of the following are sets ? Justify your answer. The collection of all the months of a year beginning with the letter J.

Which of the following are sets ? Justify your answer. The collection of all boys in your class.

Which of the following are sets ? Justify your answer. The collection of questions in this Chapter.

Which of the following are sets ? Justify your answer. The collection of ten most talented writers of India.

Which of the following are sets ? Justify your answer. A collection of novels written by the writer Munshi Prem Chand.

Which of the following are sets ? Justify your answer. A collection of most dangerous animals of the world.

Which of the following are sets ? Justify your answer. A team of eleven best-cricket batsmen of the world.

Whether the following statement is true ? Justify your answer. The set of all isosceles triangles is contained in the set of all equilateral triangles.

Whether the following statement is true ? Justify your answer. The set of all rectangles is contained in the set of squares.