What is one most important advantage of sexual reproduction?
Typically, sexual reproduction results in an individual of that species with a diverse set of genes. After all, you get half the chromosomes from your dad and half from your mom so you are a completely unique sequence of genetic information. Also, since you receive chromosomes from both parents it is sort of a redundancy in case a gene on one of the chromosome is damaged. Conversely, asexual reproduction results in a clone of the individual with no new genetic advantages.
When sexual reproduction can be advantageous is especially high during a period of unfavorable conditions. For example on Earth, there have been many time periods where conditions have not been favorable and because of sexual reproduction organisms are usually able to adapt easier to pressures from the environment. This results in changes to the organism that will be favored by the environment eventually making its way to all individuals of that species since that trait may be favored all thanks to sexual reproduction.