Short-term memory holds information for 15 to 25 seconds and stores it according to its meaning rather than just as mere stimulation. However, it is not really true that short-term memory can be retained only for this short amount of time. It has been shown in different studies that it can be held even longer.
The 3 can only be produced in the Mediterranean biome. This biome is known to have dry and wet weather. However, the summer seasons in this biome is very dry and usually lasts longer. Hence, the vegetation is found to be drought resistant. The 3 plants mentioned are known to be naturally drought resistant, hence it is in this biome that it thrives and survives best.
Sink holes and crevasses might be a result of this <span />
Algae and nitrogen-fixing bacteria are photosynthetic organisms.