In the context of relativity, mass is not an additive quantity, in the sense that one can add the rest masses of particles in a system to get the total rest mass of the system. Thus, in relativity usually a more general view is that it is not the sum of rest masses, but the energymomentum tensor that quantifies the amount of matter. This tensor gives the rest mass for the entire system. "Matter" therefore is sometimes considered as anything that contributes to the energymomentum of a system, that is, anything that is not purely gravity. This view is commonly held in fields that deal with general relativity such as cosmology. In this view, light and other massless particles and fields are part of matter.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What type of quantity is mass?
Ah, so.. unanswerable

The superstructure of a carrier (such as the bridge, flight control tower) are concentrated in a relatively small area called an island, a feature pioneered on the HMS Hermes in 1923. While the island is usually built on the starboard side of the fight deck, the Japanese aircraft carriers Akagi and Hiryu had their islands built on the port side. Very few carriers have been designed or built without an island. The flush deck configuration proved to have significant drawbacks, primary of which was management of the exhaust from the power plant. Fumes coming across the deck were a major issue in USS Langley. In addition, lack of an island meant difficulties managing the flight deck, performing air traffic control, a lack of radar housing placements and problems with navigating and controlling the ship itself.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What feature was pioneered on the HMS Hermes in 1923?
Ah, so.. an island

Quite a few words from the variety of Old Chinese spoken in the state of Wu (where the ancestral language of Min and Wu dialect families originated and which was likely influenced by the Chinese spoken in the state of Chu which itself was not founded by Chinese speakers),[citation needed] and later words from Middle Chinese as well, have retained the original meanings in Hokkien, while many of their counterparts in Mandarin Chinese have either fallen out of daily use, have been substituted with other words (some of which are borrowed from other languages while others are new developments), or have developed newer meanings. The same may be said of Hokkien as well, since some lexical meaning evolved in step with Mandarin while others are wholly innovative developments.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Many middle chinese words have retained their meanings in Hokkein but not in what?
Ah, so..
Mandarin Chinese