abstract
background
bank
big
bill
business
care
cash
concept
conceptual
conservation
conservative
conserve
creative
creativity
currency
dollar
eco
ecology
economic
economy
environment
finance
future
green
grow
growth
heap
idea
investment
isolated
large
life
money
natural
nature
note
object
pile
plant
preserve
protect
save
savings
sign
single
solution
spring
symbol
tree
white
wood