descent vs line of descent

descent and line of descent both are nouns.

Word	Noun	Adjective	Verb	Adverb
descent	Yes	No	No	No
line of descent	Yes	No	No	No

As nouns, descent and line of descent are synonyms defined as:

Other synonyms of descent include ancestry, blood, blood line, bloodline, line, lineage, origin, parentage, pedigree, stemma, stock.

As nouns, descent and line of descent are synonyms defined as:

descent and line of descent: the kinship relation between an individual and the individual's progenitors

Other synonyms of descent include filiation, lineage.

descent (noun)	line of descent (noun)
the act of changing your location in a downward direction	the hereditary derivation of an individual
properties attributable to your ancestry	the kinship relation between an individual and the individual's progenitors
a movement downward
the hereditary derivation of an individual
a downward slope or bend
the kinship relation between an individual and the individual's progenitors