How often should you change the oil and oil filter in your vehicle?

there is an explationation of this on a site called crash   course world history 1

question 1: the kuwaiti government announced us$1.5 million in aid for rohingya refugees.they pointed out that it was imperative to take immediate and concrete steps to ramp up pressure on myanmar to put an end to the violence.and said   that they r just shameful

question 2: the rohingyas were not aloud to be seen as people in myanmar.in the last few years, before the latest crisis, thousands of rohingya were making perilous journeys out of myanmar to escape communal violence or alleged abuses by the security forces.the latest exodus began on 25 august 2017 after rohingya arsa militants launched deadly attacks on more than 30 police posts.rohingyas arriving in an area known as cox's bazaar - a district in bangladesh - say they fled after troops, backed by local buddhist mobs, responded by burning their villages and attacking and killing civilians.