3. Сделайте предложения пассивными или активными. Запишите предложения. The heart pumps deoxygenated blood to the lungs. The sinoatrial node generates the electrical impulses for the heartbeat. Scientists have identified three main types of blood cells. The circulatory system transports nutrients, gases, and wastes. One-way valves ensure the proper direction of blood flow.

1. Deoxygenated blood is pumped to the lungs by the heart.
2. Electrical impulses for the heartbeat are generated by the sinoatrial node.
3. Three main types of blood cells have been identified by scientists.
4. Nutrients, gases, and wastes are transported by the circulatory system.
5. The proper direction of blood flow is ensured by one-way valves.

Ответ: Deoxygenated blood is pumped to the lungs by the heart. Electrical impulses for the heartbeat are generated by the sinoatrial node. Three main types of blood cells have been identified by scientists. Nutrients, gases, and wastes are transported by the circulatory system. The proper direction of blood flow is ensured by one-way valves.