Reabsorbtion. Occuring more commonly within the nephron system than filtration, this is a form of active transport which takes the the useful substances for the body from the tubules and places them back into the blood filled capillaries.
Oleanders are shrubs, but they are _big_ shrubs. Most of the varieties in cultivation top out at 8 to 12 feet tall and about the same width. The wild form, and some of the older cultivars used for windbreaks top out at 20 x 20 feet.
It's native to northern Africa and the eastern Mediterranean. This fast-growing evergreen shrub or small tree can be used in your garden as a living screen or wall. With pruning, oleander can be kept at a shrub height, or it can be trained into a small tree reaching between 10 and 18 feet tall.