The FREQUENCY of light remains unchanged once it leaves the source.
Answer:
A
Explanation:
Begin as protostars, which fire up when they collapse and become denser and hotter.
A. Genus and B. Species are also major levels of classification.
Explanation:
Given that,
A person walks 9.0 km directly east and then turns left and heads directly north for 12.0 km.
We need to find his displacement from the starting position.
We know that,
Displacement = shortest path covered

For direction,

Hence, this is the required solution.