Answer:
genes from the nucleus of a eukaryotic algal endosymbiont
Explanation:
Given: Chlorarachniophyte and cryptophyte algae contain three sets of genetic material: the nuclear genome, the chloroplast genome, and a set of genes found in the nucleomorph.
Here, nucleomorph genes represent genes from the nucleus of a eukaryotic algal endosymbiont
Secondary endosymbiotic acquisition of photosynthesis results in the transitional forms - Cryptophyte and chlorarachniophyte algae.