When a blood drop lands on a surface at a 90 degree angle, what shape is the drop in typically?
an oval
a circle
a sphere
the angle makes no difference in the shape of the drop.
i need

It's a circle. 90 degrees means it's falling straight down.
The more horizontally the blood drop flies onto a flat surface, the more thinner it looks.

Definitely not a sphere, that's a 3-D shape

The infrared (ir) and the ultraviolet(uv) represent the two extremities of the visible spectrum (400-700nm). while ir represents electromagnetic radiation with wavelengths longer than those of visible light, uv represents wavelengths shorter than visible light

The zone your looking for is the intertidal zone.