Which transition should the writer use to replace To start, to most logically connect the ideas in the paragraph? There are many reasons to adopt an animal from a shelter. Adopting saves lives and makes room for more animals to receive help. Adopting is less expensive than buying a pet, and shelter pets are often already trained and socialized. To start, adopting gives homeless animals a second chance in a loving home. And adopters gain a new best friend!
Most importantly,
Because of this,
In a different way,
For example,