Kinda easy but too lazy

What is meant by the statement" the melting poin of glycerine is 13 degree celsius

Henry, whose mass is 95 kg, stands on a bathroom scale in an elevator. the scale reads 830 n for the first 2.4 s after the elevator starts moving, then 930 n for the next 2.4 s. part a what is the elevator's speed 4.8 s after starting? express your answer with the appropriate units.

What component of earth’s atmosphere exists entirely as a result of photosynthesis?