Question

why sun appear red in morning

Answer 1

At morning, the sun is near to the horizon.
It needs to travel a large distance before reaching out eyes.
While covering this distance, most of the blue light gets scattered away. But the red light with longer wavelength does not get scattered easily.
As a result, the sun appears red in the morning.
Hope it helps you

Answer 2

In the morning the sunlight covers a larger distance and thick layers of atmosphere so except the red colour light most of the other colours are scattered into the atmosphere as only red colour light reaches our eye the morning sun appears to be red