Given a scientific passage and an answer, generate a question for the given answer.

Passage: "Dry ice," or solid carbon dioxide, is a substance that sublimes at atmospheric pressures. Dry ice is very cold (78C) and so is used as a coolant for goods such as ice cream that must remain frozen during shipment. Because the dry ice sublimes rather than melting, there is no liquid mess associated with its change of state as the dry ice warms. As you may have seen in demonstrations, dry ice merely transforms from a solid to a cold, steamy looking gas. Ferrocene (an iron-containing compound) is usually purified by sublimation by gentle warming at atmospheric pressure. In the Figure below , you can see the reddish ferrocene crystals deposited on the outside of that tube. Deposition is the change of state from a gas to a solid. Answer: dry ice
What is the common term for solid carbon dioxide, which is used as a coolant?

Passage: Although most of a cell's DNA is contained in the cell nucleus, mitochondria have their own DNA. Mitochondria also have the machinery to manufacture their own RNAs and proteins. The human mitochondrial DNA sequence has 16,569 base pairs encoding 37 total genes: 22 tRNA genes, 2 rRNA genes, and 13 peptide genes. The 13 mitochondrial peptides in humans are integrated into the inner mitochondrial membrane, along with proteins encoded by nuclear genes. Answer: nucleus
Where is most of the cell's dna contained?

Passage: The size of particles determines how they are carried by flowing water. This is illustrated in Figure below . Answer: size
What characteristic of particles determines how they are carried by flowing water?