Self-certification. Employers can also ask employees to fill in a form when they return to work to confirm theyâve been off sick for up to 7 days. This is called âself-certificationâ. Employers usually provide their own version of this form.elf-certification. Employers can also ask employees to fill in a form when they return to work to confirm theyâve been off sick for up to 7 days. This is called âself-certificationâ. Employers usually provide their own version of this form.
Â· just now. 1  The most massive stars (OB stars) have the shortest life. K and M stars are the least massive and have the longest lives. 2  McGarnigle is the most correct here. Type O and B are the hottest, most massive stars and, by virtue of their extreme mass, are the shortest lived.
Main-Sequence Lifespan. The main sequence is the stage where a star spends most of its existence. Relative to other stages in a star's life it is extremely long; our Sun took about 20 million years to form but will spend about 10 billion years (1 Ã 10 10 years) as a main sequence star before evolving into a red giant.