Remember, fleas and ticks can survive for a long time away from their host in certain stages of the life cycle. (petco.com)
As parasites are evident on a fecal analysis only in certain stages of their life - cycle, a «negative» fecal does NOT mean that your pet is clear of parasites. (litchfieldvet.com)
We were more focused on the genetics — the livestock breeding of salmon for the normal traits of survival at certain stages of the life cycle, productive growth and feed conversion, and egg production.» (scientificamerican.com)