Can I ask a question why people have become insensitive

They don't become insensitive coz it is hard for someone to change

it's just their nature

either they adopt easily or it's what they are

here's the link to your question!

explanation:

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer