The diagram illustrates part of the circulatory system in a mammal. In which part are blood pressure and flow speed at their lowest?
- Alowest blood pressure at 1; lowest speed of flow at 4
- Blowest blood pressure at 2; lowest speed of flow at 3
- Clowest blood pressure at 3; lowest speed of flow at 2
- Dlowest blood pressure at 4; lowest speed of flow at 1