Kellen Browning

In a major moment in Apple’s efforts to fend off growing scrutiny of its power, Tim Cook took the stand in a trial for the first time as Apple’s chief executive and defended his business from accusations that it hurt app makers to expand its profits.

Millions of children are encountering all sorts of inconveniences that come with digital instruction during the coronavirus pandemic. But many students are facing a more basic challenge: They don’t have computers and can’t attend classes held online. A surge in worldwide demand by educators for low-cost laptops and Chromebooks — up to 41 percent higher than last year — has created monthslong shipment delays and pitted desperate schools against one another.