A. We don't actually do two, or three or 10 things at once, we just switch from one to another to another.

B. Multitasking makes us demonstrably efficient, increasing cognitive performance.

C. Each time we shift attention, there is a metabolic cost we pay in glucose.

D. Some brain activities are more expensive than others, and switching attention is among the most expensive.

A. Muhammad Ali’s rejection of the Vietnam War was thus a rejection of war itself as a viable means of solving human problems, real or perceived.

B. In refusing the draft, Ali thus also refused to believe that national boundaries somehow categorically divided human beings into “us” and “them”.

C. Violence is the tool of the hegemon; by eschewing it you are already challenging the means through which hegemony is legitimized.

D. The best way to stand up to power and injustice is to be steadfast in your resistance while shunning violence.

A. There are few more emotional ways to view history than through the lens of a camera.

B. To take photographs is to hold one’s breath when all faculties converge in a face of fleeing reality.

C. They are not about dialing for quotes or quick sound bites.

D. Photographs convey the ultimate journalistic credo: to be present at the site of action at the right time, and alive to capture the fleeting moments that transform our lives.

A. If we are not to make grievous mistakes in the name of good things such as fighting corruption or tackling crime, then we, the people, must reflect.

B. The problem is not of manipulation or political ambition; it is the willingness with which otherwise sensible citizens allow themselves to follow the Piper.

C. If we realize that it is our sentiments that are disturbed, not our security, perhaps we will see the issue with greater equanimity.

D. It is in the nature of democratic politics for ambitious politicians to use emotions to climb up the ladder of power.

A. As global warming speeds up the melting of these glaciers, this weight is lifting, and the surface slowly is springing back.

B. Though the average hiker wouldn't notice, the Alps and other mountain ranges have experienced a gradual growth spurt over the past century or so.

C. These glaciers are giant scrapers that carve out valleys and carry away rock debris on ice conveyor belts, sculpting mountains.

D. For thousands of years, the weight of the glaciers atop these mountains has pushed against the Earth's surface, causing it to depress.