Nearly all eukaryotic cells contain a class of small, round organelles that contain oxidative enzymes. the enzymes break down organic substances via oxidation reactions. what are these organelles called?

The correct answer is peroxisomes.  

Peroxisome refers to a small organelle found in the cytoplasm of various cells that comprises catalase (the reducing enzyme) and generally some oxidases.  

They are the minute vesicles and comprises the digestive enzymes used for dissociating toxic components in the cell. They are not similar to lysosomes on the basis of the kind of enzymes they withheld. The peroxisomes generally contain enzymes that need oxygen, that is, oxidative enzymes.  

answer; the above statement is (true);

the answer is d. chordata