Questions

Stars twinkle because they’re so far away from Earth that when light from the stars passes through the atmosphere, it is bent countless times due to refraction, making it look like as if they were blinking. The sun and other planets doesn’t twinkle because it’s too close to Earth compared to other stars.

"National Volunteer Day" & "International Peace Day" are observed on 21st september every year.

True, The luster of a metal is due to presence of free electrons. Luster means shine or soft glow. We know that metals have the quality of reflecting light from its surface.

S-phase (synthesis phase) is the part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase. Precise and accurate DNA replication is necessary to prevent genetic abnormalities which often lead to cell death or disease.