If everyone in their respective field gives 100% dedication and honestly do whatever task given to them then I think everybody serves the nation their respective ways directly or indirectly.
I that sense I think soldier undoubtedly serves that nation. They sacrifice their family, friends, money, leisure life and risk their lives to protect common people. they serve directly.
whereas teachers, scientists, politicians also have their part to build a nation. for the betterment of the nation everybody must do their own job with perfection and dedication
"Teachers, I believe, are the most responsible and important members of society because their professional efforts affect the fate of the earth
"Guru Brahma Gurur Vishnu
Guru Devo Maheshwaraha
Guru Saakshat Para Brahma
Tasmai Sree Gurave Namaha "
Meaning: Guru is verily the representative of Brahma, Vishnu and Shiva. He creates, sustains knowledge and destroys the weeds of ignorance. I salute such a Guru.
Teacher is the person who can help us cross this ocean of life, the one who can reveal to us
d divine