Which point on the demand curve represents the highest quantity demanded?

on this day in 1939, in response to hitler’s invasion of poland, britain and france, both allies of the overrun nation declare war on germany.

the first casualty of that declaration was not german—but the british ocean liner athenia, which was sunk by a german u-30 submarine that had assumed the liner was armed and belligerent. there were more than 1,100 passengers on board, 112 of whom lost their lives. of those, 28 were americans, but president roosevelt was unfazed by the tragedy, declaring that no one was to “thoughtlessly or falsely talk of america sending its armies to european fields.” the united states would remain neutral.

as for britain’s response, it was initially no more than the dropping of anti-nazi propaganda leaflets—13 tons of them—over germany. they would begin bombing german ships on september 4, suffering significant losses. they were also working under orders not to harm german civilians. the german military, of course, had no such restrictions. france would begin an offensive against germany’s western border two weeks later. their effort was weakened by a narrow 90-mile window leading to the german front, enclosed by the borders of luxembourg and belgium—both neutral countries. the germans mined the passage, stalling the french offensive.

take five to 10 minutes to warm up and cool down properly.

plan to start slowly and boost your activity level gradually unless you are already exercising frequently and vigorously.

be aware that training too hard or too often can cause overuse injuries like stress fractures, stiff or sore joints and muscles, and inflamed tendons and ligaments. sports prompting repetitive wear and tear on certain parts of your body — such as swimming (shoulders), jogging (knees, ankles, and feet), tennis (elbows) — are often overuse culprits, too. a mix of different kinds of activities and sufficient rest is safer.

listen to your body. hold off on exercise when you're sick or feeling very fatigued. cut back if you cannot finish an exercise session, feel faint after exercise or fatigued during the day, or suffer persistent aches and pains in joints after exercising.

if you stop exercising for a while, drop back to a lower level of exercise initially. if you're doing strength training, for example, lift lighter weights or do fewer reps or sets.

for most people, simply drinking plenty of water is sufficient. but if you're working out especially hard or doing a marathon or triathlon, choose drinks that replace fluids plus essential electrolytes.

choose clothes and shoes designed for your type of exercise. replace shoes every six months as cushioning wears out.

for strength training, good form is essential. initially use no weight, or very light weights, when learning the exercises. never sacrifice good form by hurrying to finish reps or sets, or struggling to lift heavier weights.

exercising vigorously in hot, humid conditions can lead to serious overheating and dehydration. slow your pace when the temperature rises above 70°f. on days when the thermometer is expected to reach 80°f, exercise during cooler morning or evening hours or at an air-conditioned gym. watch for signs of overheating, such as headache, dizziness, nausea, faintness, cramps, or palpitations.

dress properly for cold-weather workouts to avoid hypothermia. depending on the temperature, wear layers you can peel off as you warm up. don't forget gloves.