I know this isn't hard I'm just losing braincells

Astructural difference between the trachea and esophagus that prevents the trachea from collapsing is the presence of: a) smooth muscle b) skeletal muscle c) respiratory cilia d) rings of cartilage

What is the objective ethical ideal

Viruses ) manufacture their own atp, proteins, and nucleic acidsb) use the host cell to copy themselves and make viral proteinsc) use the host cell to copy themselves and then viruses synthesize their own proteinsd) metabolize food and produce their own atp