What do you understand by the following :

What do you understand by the following :
(a) Century, (b) Shake, © Lunar month, (d) Leap year, (e) Tropical year.

It is the largest unit of time,
1 century = 100 years.
(b) It is the smelliest unit of time, 1 shake = ${{10}^{-8}}$ sec.
© It is the time taken by the moon to complete one revolution around the earth; 1 lunar month 29.53 days.
(d) A year which is divisible by 4 and in which the month of february is of 29 days is called leap year.
(e) The year in which total solar eclipse takes place is
called tropical year.