question:
Bell also built the Bell Boatyard on the estate, employing up to 40 people building experimental craft as well as wartime lifeboats and workboats for the Royal Canadian Navy and pleasure craft for the Bell family.
How many people worked for the Bell Boatyard?

answer: yes

question:
Meanwhile, the Industrial Revolution laid open the door for mass production and consumption.
What became cheap enough for the middle class to buy?

answer: no

question:
Double-slope stills are the most economical for decentralized domestic purposes, while active multiple effect units are more suitable for large-scale applications.
What is used to make saline or brackish water drinkable?

answer: no

question:
Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP).
How is sunlight converted into electricity?

answer:
yes