probably causes most variations in individuals ? Sunlight b . gene mutations c . poisons d. cell phones

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.

thats a little if u want the answer just look it up on google thats what i do haha : )

a electronegativity decreases beacuse the size of nucleus is bigger.