Help please I need this for bio

Apart of the periodic table is shown. a portion of the sixteenth and seventeenth columns of the periodic table is shown. column 16 reads eight oxygen, 16 sulfur, and 34 selenium. column 17 reads nine flourine, 17 chlorine, and 35 bromine. which of the following elements is less reactive than the others? bromine (br) oxygen (o) selenium (se) sulfur (s)

50 points! which of the following is an inference? a burning candle is extinguished when it is covered with a jar. the candle burns longer than expected in a jar that has a plant in it. a plant lives longer than expected in a jar that has a burning candle. there is more oxygen in the jar because there is a plant in it.

How can we use spectral lines of light coming from the superclusters to identify which is receding from earth at the slowest rate.