A tendon is a fibrous connective tissue which attaches muscle to bone. Tendons may also attach muscles to structures such as the eyeball. A tendon serves to move the bone or structure. A ligament is a fibrous connective tissue which attaches bone to bone, and usually serves to hold structures together and keep them stable.
I am going to assume you meant the "first trophic level" of the ecosystem. The first tropic level of an ecosystem is made up of producers, so the answer is C, Acorns.
