The protist known as an euglena is sometimes considered an animal-like protist and other times a plant-like-protist. why would scientists classify it as an animal-like protist?

Euglena is unicellular micro-organism which belongs to protista kingdom, mostly found in fresh water. Because of their unique characteristics sometimes they are considered as plant-like and sometimes animal-like.

Most of the euglena contains photosynthesizing chloroplast within the body of the cell, like plants.

Euglena cell contain flagella and tail which allow moving, it is the characteristic of animal like. When euglena goes into the darkness environment it's cell will engulf the food by phagocytosis. They have eyespot which is sensitive to light and compair to modern eye and these are the characteristic of animals.

This is why they are considered as both plant and animal-like.

sex cells are usually half's then they find another half and make a fertilize egg