Evolutionary history of an organism is known as A. PhylogenyB. AncestryC. PaleontologyD. Ontogeny

The correct answer is A. Phylogeny.

Explanation:
Phylogeny: Phylogeny refers to the evolutionary history and relationships among different species or groups of organisms. It is often represented in the form of a phylogenetic tree, which shows how species have evolved from common ancestors over time. This term specifically addresses the lineage and branching patterns of evolution.

Ancestry: While "ancestry" pertains to the lineage of an organism (its direct ancestors), it does not encompass the broader evolutionary history involving multiple species or groups. It is a more limited term compared to phylogeny.

Paleontology: Paleontology is the study of ancient life through fossils. While it provides evidence for phylogeny, it is not synonymous with the evolutionary history of an organism.

Ontogeny: Ontogeny refers to the development of an individual organism from a zygote to its mature form. It does not describe the evolutionary relationships or history of a species.

Thus, phylogeny is the correct term for the evolutionary history of an organism.