He made a decision about the problem.

We decided on our travel destination for tomorrow.

Education about sex is very important.

Sex chromosomes play a crucial role in determining the sex of an organism.

He succeeded in staining the cells.

He stained his shirt with wine.

We have a responsibility to protect the biodiversity of the Earth.

He received the letter challenging him to a duel and began preparing for the duel.

What is this organism?

His role is to fulfill his responsibilities as a leader.