20.
They told me that my answer was too short so I'm just adding this on, don't mind me.
A derived trait is a trait that the current organism has, but the previous one did not have.An ancestral trait is a trait that you, and your ancestors had.A vestigial structure is a structure that had some sort of use in your ancestor, but none in your current body
The troposphere is shallowest or narrowest at the poles, and deepest or thickest at the equator. At the geographic North and South Poles, the troposphere reaches only 4 miles high, while at the equator, it extends nearly 12 miles high.
The 'cheek' is the common name for the insect GENA.
The gena is located in the head area of insects. The gena forms the sclerotized area on each side of the head, below the compound eyes, which extends to the gular structure. The gena varies among species of insects.
Passive Transport: Simple Diffusion. Diffusion across a cell membrane is a type of passive transport, or transport across the cell membrane that does not require energy. ... Molecules that are hydrophobic, just like the hydrophobic region, can pass through the cell membrane by simple diffusion.