Concepts: body, orbit, spacecraft
A: bodies with heliocentric orbit seen by the spacecraft
Concepts: circle, derive, equation
A: deriving the equation of a circle
Concepts: city, tourist, town
A: donkeys start their search for carrots from tourist in the old mining town of a city
Concepts: apartment, balcony, terrace
A:
every apartment has access to its own private external balcony or terrace