Which of these can the Doppler effect be used to deduce in astronomy?
A.
the shape of the orbital path of an object
B.
whether the object is traveling toward or away from us.
C.
the chemical composition of the object
D.
the type of spectrum the object emits

Lunches in us high schools are lacking adequate nutritional value. the menus have become increasingly varied over the past two decades, and they are varied to a fault. now high school students can choose between healthy main dishes and "junk food" items offered à la carte on the school menu. milkshakes and fries are often the lunch of choice for america’s youth. fourteen-year-old alira sanson from grand rapids, michigan, admits, "i love my high school's menu. it is much better than middle school food. i eat a giant chocolate chip cookie and a bag of chips for lunch every day—because i can." the middle school menu alira refers to is the government-regulated hot lunch mandated in elementary and middle schools across the nation. lunches at the high school level are often under site-based management, and food service officials are under pressure to provide food that sells. this pressure renders unhealthy choices, and the resulting menus are detrimental to students. what is the topic of this passage? a. high school food is better than middle school food. b. high school students can choose their lunches, but middle school students cannot. c. a comparison of hot lunches in the united states d. the nutritional value of high school lunches