A/n front is a type of collision in which cold, dense air displaces warm air, and forces the warm air up along a steep slope.
a. warm
b. cold
c. stationary
d. occluded

The right option is; B. cold

A cold front is a type of collision in which cold, dense air displaces warm air, and forces the warm air up along a steep slope.

Cold front is the boundary of a cooler mass of air that replaces a warmer mass of air at ground level which is positioned within a fairly sharp surface of a low pressure system. Cold fronts normally move from northwest to southeast and they are usually weak in the summer and strong in the spring and fall. Cold front causes thunderstorms, rain and strong shifting winds.

thrombocytopenia, which is a deficiency in blood platelets, can cause bleeding and bruising in the dermis similar to senile purpura. other possible causes include: exposure to ultraviolet rays and aging skin are common causes of senile purpura. senile purpura may also be a sign of collagen loss in the skin and bones.