What is the best transition to add at the beginning of the third sentence?

Dogs make wonderful pets because they us stay happy and healthy. the topic sentence is "dogs make wonderful pets." , is this correct? i keep doubting myself.

What language uses emotionally words

Write a literary analysis essay about an intercalary chapter of the grapes of wrath. your essay should examine how the structure and language support the overall purpose, and it should include specific examples from the text to support your claim. your essay should include the following elements: • a claim that takes a clear stand on the author's purpose, supported by main points • evidence from the text that supports your claim and main points • commentary that the reader understand how your evidence should be interpreted • an introduction, body and conclusion that organize the content of your essay