Which word from the paragraph best the reader understand the meaning of the underlined word?

natalie mixed blue food coloring into the vanilla frosting. the diffusion of color was immediate. at first it was a light blue. but as she added more coloring, the spread of blue became darker in the frosting. it looked great on the giant cookie.

a.
frosting

b.
spread

c.
cookie

d.
coloring

the underlined word is diffusion.

Bicycle riding should be encouraged, and adding bicycle lanes will increase the number of riders. it is healthier for people to ride than to sit angrily in traffic. it is healthier for everyone to breathe cleaner air. sharing the road can be tricky, but there are things that can be done. so, add the bike lanes and get rolling! which sentence would improve this conclusion? every town should consider adding bicycle lanes, because it is a great idea. organizing safety classes for drivers and cyclists will ensure that everyone knows the rules. do not listen to negative people who complain about anything new. it is true that some people might get injured, but even walking can be dangerous.