Examine the statements below and choose the correct answer:
1.
| Assertion (A): | In human heart, there is no mixing of oxygenated and deoxygenated blood. |
| Reasoning (R): | Valves present in the heart allows the movement of blood in one direction only. |
2.
| Assertion (A): | The walls of the ventricles are thicker in atria. |
| Reasoning (R): | Thick ventricle walls helps to prevent the backflow of blood. |
3.
| Assertion (A): | In molluscs, the circulatory system is of closed type. |
| Reasoning (R): | In closed type circulation, blood pumped by the heart passes through blood vessels into haemocoel. |