What’s the differences between the three main classes of sponges.

There are three classes. These classes include Calcerea, Desmospongia, and Hexactinellida. They are divided into these classes based mostly on the composition of their spicules and skeletal fibers. (spicules are rod-shaped cellular projections that make up the skeleton of sponges) hope this helps!

Explanation:

cancer   is   essentially   uncontrolled   mitosis   of specialized cells

hey bro i looked it up on google the structure of the eye-spot in euglena viridie, e. ehrenbergii, and phacus pyriyorme is not as franzé haa described it. the so-called “crystal body” and “lens bodies” were not found in any of the individuals of the species examined by me. as earlier observers have stated, the eye-spot consists simply of a mass of pigment granules arranged in a single layer, and probably embedded in a protoplasmic framework, but the latter could not be seen, and its presence was only inferred from the fact that the pigment granules must be held together in some way, thd the eye-spot as a whole is capable of expansion, and that the pigment granules can be separated from each other.

hope this   and an i get brainlsiest