This would be a cryogenic intermodal tank. These are used to store and transport HAZMAT gases that require storage under specific pressure and temperature parameters. Cryogenic Intermodal tanks have pressure of 25 Psi or less.
The most massivest stars end their lives as black holes. <em>(D)</em>
Similar elements with similar properties were in the same groups and periods for instance lithium(Li) and sodium(Na) are alkaline metals and so belong to the same group (that is group 1).Also Hydrogen(H) and Helium(He) both have only one shell or energy level and so belong to the same period.