The weather is warm and dry Which change would bring a cold front in

A. several days of gray skies

A. dry air and sunny skies

B. rain or thunderstorms

C. extended period of rain or snow

Which step in naming unsaturated hydrocarbons is used for alkenes but not alkynes

May someone me with these science questions

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?