Categorise the following plants into hydrophytes,halophytes,mesophytes,and xerophytes. Give reasons for your answers.
$(a)$ Salvinia $(b)$ Opuntia $(c)$ Rhizophora $(d)$ Mangifera

(N/A) Salvinia is a hydrophyte because it is an aquatic plant that grows in water.
$(b)$ Opuntia is a xerophyte because it is adapted to survive in arid,dry environments with limited water availability.
$(c)$ Rhizophora is a halophyte because it grows in saline,marshy environments like mangroves and possesses specialized roots for salt tolerance.
$(d)$ Mangifera is a mesophyte because it grows in environments with moderate water availability,which is typical for most terrestrial plants.