What does the line of blue triangles mean on a weather map?

a warm front

a cold front

a stationary front

an occluded front

It represents a cold front corespondent to its color

Hope this helps!!

B. a cold front

Explanation: Blue triangles represent a cold front advancing in the direction of the triangles, as cooler air displaces warmer air upwards. Red semicircles are a warm front, where warmer air pushes the cooler air away.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.