What observations would indicate that a material is a pure substance

Someone, part 1: which compound does c represent? part 2: name a process that could release this compound into the air. part 3: explain how the elements that form it are conserved during the carbon cycle. use complete sentences to explain your answer. justify how this compound was created from a recycling of carbon in the carbon cycle. use complete sentences to explain your answer.

Microtubular fibers that assist in the movement of chromosomes during nuclear division in conjunction with proteins, makes up the small and large organelle pieces that assemble prior to translation three-base nucleotide sequence that can complementarily pair with the functional transcript, allowing a particular material to be brought to a ribosome particular time in the cell cycle when the cell’s systems determine if the cellular conditions are appropriate to continue through the cycle time in the cell’s cycle when proteins are made and organelles are duplicated enzyme that allows proper nucleotide bonding during transcription specific dna sequence which will initiate gene transcription division of the cell’s cytoplasm specific bond that forms between two amino acids when a carboxyl group binds to a amino group three-base sequence that does not code for a particular amino acid a paired organelle which facilitates the formation of movement microtubules time in the cell’s cycle when the microtubular structures exert an equal pressure on the cell’s genetic material

A50.0g sample of liquid water at 0.0 c ends up as ice at -20.0 c. how much energy is involved in this change?