There is in fact no such thing as art for art's sake, art that stands above classes, art that is detached from or independent of politics. Proletarian literature and art are part of the whole proletarian revolutionary cause.
Some plants are carnivores, gaining nutrients by eating various small insects and spiders. A well known example of a carnivorous plant is the Venus Flytrap.
Alkali metals such as sodium, potassium, rubidium, caesium and francium are extremely reactive elements, just putting them in water can result in an explosion! They are carefully stored in oil to prevent this happening.
While aluminum is the most common metal found in the Earth's crust, the most common metal found on Earth is iron, mostly because it makes up such a large part of the Earth's core.