This paper is concerned with
the investigation of some interplay between the theories of (Kurosh-Amitsur) radicals
and varieties of (not necessarily associative) algebras. Specifically, it is shown that a
variety is a radical class if and only if it is closed under extensions, while a
radical class which is also a semi-simple class is the same thing as a variety
with attainable identities in the sense of T. Tamura (J. Algebra 3 (1966),
261–276). In certain instances it is shown that the two properties of varieties are
equivalent.