How did people on the home front show that they had family members who were in the service or were killed in action?

i think i will need more detail to answer if this is a specific question on a test, but technology advancements are good for many industries, such as medicine or food industries, new technology could us in medicine in ways such as new scanners to tell us more about our bodies or new cures or vaccines for diseases.

wealth comes from those who are the most hard working and   competent

the answer would be d.