No, there is no apostrophe in the phrase "21st century."
In the modern 21st century.
Yes, idleness has a suffix. The suffix is -ness.
"Shaping Better 21st Century Learners With English"
idleness, leisure
We are in the 21st Century.
21st century.
2030 is in the 21st century.
the 21st century
~this is the 21st century
Yes they do have batteries in the 21st century and had in the 20th century.
No, there is no apostrophe in the phrase "21st century."
is 21st century is an age of greed
The year 2010 is in the 21st century.
characteristics of 21st century managers
AD 2015 was in the 21st century
The twenty-first century (21st or XXI) ranges from years 2001 to 2100, so until 2101 it is the 21st century.