Why is cartilage important? a. it contains a fluid that enables the surfaces of bones to slide over each other smoothly at the joints. b. it acts as a cushion between bones and protects them as they move against each other. c. it holds bones together at the joints. d. it causes bones to fuse together as they grow.

Cartilage is important for many reasons, but primarily because it "B. It acts as a cushion between bones and protects them as they move against each other." Most of this happens at the joints.

Both prokaryotic and eukaryotic cells have ribosomes and cell membranes

Proteins are the workhorses of the cell, controlling virtually every reaction within as well as providing structure and serving as signals to other cells. proteins are long chains of  amino acids  , and the exact sequence of the amino acids determines the final structure and function of the protein. instructions for that sequence are encoded in  genes  . to make a particular protein, a messenger ribonucleic acid (mrna) copy is made from the gene (in the process called  transcription  ), and the mrna is transported to the  ribosome  . protein synthesis, also called  translation  , begins when the two ribosomal subunits link onto the mrna. this step, called initiation, is followed by elongation, in which successive amino acids are added to the growing chain, brought in by transfer rnas (trnas). in this step, the ribosome reads the  nucleotides  of mrna three by three, in units called  codons  , and matches each to three nucleotides on the trna, called the anticodon. finally, during termination, the ribosome unbinds from the mrna, and the  amino acid  chain goes on to be processed and folded to make the final, functional protein