Non-specific line of defense, external defense, the skin, sweat, mucus, tears and saliva blocks or traps bacteria and foreign invaders from entering
the body *
Defense?

sorry, is there a picture? i do not see any arrows.

wut? unius0123 wut?

the circled areas are referred to   as sunspots.   the sunspots are cooler than the   surrounding area.

sunspots are temporary phenomena on the photosphere of the sun that appear visibly as dark spots compared to surrounding regions. they correspond to concentrations of magnetic field flux that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere.

other quantities, called derived quantities, are defined in terms of the seven base quantities via a system of quantity equations. the si derived unitsfor these derived quantities are obtained from these equations and the seven si base units.