Write in which animals blood does not carry oxygen throughout the body. How can this be explained?

Intestinal, flat and round worms do not have a circulatory system. Oxygen enters their body through the integument of the body.
Of all animals that have a circulatory system, insects’ blood does not participate in the transport of oxygen. This is due to the peculiarity of their movement. In flight, their body requires a huge amount of energy, which is released during the oxidation of substances. So that it is released quickly from the spiracles, air enters the respiratory tubes – the trachea, which deliver it directly to the organs.