sieve tube vs bast

sieve tube and bast both are nouns.

Word	Noun	Adjective	Verb	Adverb
sieve tube	Yes	No	No	No
bast	Yes	No	No	No

sieve tube (noun)	bast (noun)
tube formed by cells joined end-to-end through which nutrients flow in flowering plants and brown algae	(botany) tissue that conducts synthesized food substances (e.g., from leaves) to parts where needed; consists primarily of sieve tubes
	strong woody fibers obtained especially from the phloem of from various plants