The ability to reproduce is essential for a species, but not for an individual. There are some people that can't reproduce, but they're still alive!
Uniform velocity means no Net force and therefore no acceleration. Acceleration only happens when the velocity changes.
Every organism may classified into seven level of classifications, such that each level contains organisms with similar characteristics. Kingdom is the largest and the broadest level of classification while species is the smallest and most specific level of classification. Therefore from the largest to the smallest the order is as follows:
Kingdom
Phylum
Class
Order
Family
Genus
Species
