Collect the information about the animals which communicate through Infrasonics or ultrasonics. Collect their pictures and write a report on their communication technique.

Collect information about the path of revolution of moon around the earth and write a report.

Collect the information about the base area and stability of some objects with different shapes and write a report.

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

Which of the following are primary and secondary data? i. Collection of the data about enrollment of students in your school for a period from 2001 to 2010. ii. Height of students in your class recorded by physical education teacher.