What is the flower/plant that stands for: elevation?

Questions

[science and technology] what do the initials NASA of the us government agency for space flight represent?

[science and technology] what is a chuckwalla?

[science and technology] how many pockets has a snooker table?

[science and technology] what first appeared beside the roads outside the huses of parliament in 1868?

[science and technology] what are romney marsh, suffolk and swaledale?