SC GPrep

[RonPurewal]

Sorry to dig this old one.
isn't their in BDE problematic? shouldn't it be it's ?

you are correct; "their" is problematic.

on the other hand, "its" wouldn't work here, either.
you can't use any pronoun for "black rhino" here, because, in this sentence, "black rhino" is not a noun. it's an adjective describing "population".

[aflaamM589]

Sorry Ron, i couldn't get you.
its is possessive pronoun,
in Africa’s black rhino population , population is noun while Africa’s black rhino is adjective
Therefore, its can go back to Africa’s black rhino .
Isn't this line of reasoning valid?
Best

[tim]

"its" is a possessive adjective. "Africa's black rhino" is not.