Yes, PROTOZOA is a Scrabble word!

Letter values in Scrabble US: P 3, R 1, O 1, T 1, O 1, Z 10, O 1, A 1.

Is it a valid word?

PROTOZOA is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

in some classifications considered a superphylum or a subkingdom; comprises flagellates; ciliates; sporozoans; amoebas; foraminifers
any of diverse minute acellular or unicellular organisms usually nonphotosynthetic

Also: phylum protozoa.