zygote: (genetics) the diploid cell resulting from the union of a haploid spermatozoon and ovum (including the organism that develops from that cell)
cell: (biology) the basic structural and functional unit of all organisms; they may exist as independent units of life (as in monads) or may form colonies or tissues as in higher plants and animals
wolstonian glaciation: the next-to-last Pleistocene glaciation in Britain and the deposits laid down at that time