Can someone answer this please?

"Fat cell, yellow bone marrow, femur, nervous system."

Explanation:

Via process of elimination, we can eliminate the first and last answers, as the biggest unit of a single organ system would be the entirety of the system, and those have the system itself jumbled in between the list.

That leaves us with the center-two answers. I believe "bone" is too vague, meaning that bone, in some cases, may be smaller than cartilage, thus, leaving you with the above answer.

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