To prevent blood flowing back after each heartbeat. They ensure that the blood flows only in one direction (back to the heart).
Tissue damage activates nociceptors or pain receptors in the skin. A signal is sent to the peripheral nerve to the spinal cord where neurotransmitters or chemical messengers are released. It activates other nerves to pass signal to the brain. The signals are relayed to the somatosensory cortex for sensation, frontal cortex for thinking and limbic system for emotional response.
This is only explanation. What are the questions for it?
Answer:
Differences in temperature or precipitation determine the types of plants that grow in a given area (Figure 1). Generally speaking, height, density, and species diversity decreases from warm, wet climates to cool, dry climates. Raunkiaer (1934) classified plant life forms based on traits that varied with climate.
Explanation:
