The tree is . . . . . . . . the house. Which preposition is suitable to fill the blank?

My cousin has invested a lot of money . . . . . . . . farming.

She was a devoted wife and looked . . . . . . . . her husband.

The boxer was . . . . . . . . his guard when his opponent threw a right book.

He got success due . . . . . . . . hard work.

He will be with you . . . . . . . . a moment.

Unlock him . . . . . . . . 7 in the morning.

Who is older . . . . . . . . you two?

The chiropractor jumped . . . . . . . . his back.