Answers for "bootstrap row types"

bootstrap breakpoints

// Small devices (landscape phones, 576px and up)
@media (min-width: 576px) { ... }

// Medium devices (tablets, 768px and up)
@media (min-width: 768px) { ... }

// Large devices (desktops, 992px and up)
@media (min-width: 992px) { ... }

// Extra large devices (large desktops, 1200px and up)
@media (min-width: 1200px) { ... }

bootstrap screen sizes

The Bootstrap grid system has four classes:
xs (for phones - screens less than 768px wide)
sm (for tablets - screens equal to or greater than 768px wide)
md (for small laptops - screens equal to or greater than 992px wide)
lg (for laptops and desktops - screens equal to or greater than 1200px wide)