Answer: B. Two
Explanation:
During the first stage, your body starts relaxing and falling into sleep. This is the lightest stage of sleep. You can wake easily during this stage, and are not "fully" asleep.
During the second stage, your body deepens into it's sleep, your heart rate decreases, your body temperature decreases, and more. <em>This is the stage that "represents the beginning of actual sleep" which is the answer to your question.</em>
During the third stage, your body is in a deeper state of sleep. Your muscles relax further, your breathing rate slows, and more.
During the fourth stage, your heart rate and body temperature rise again. Your brain is a bit more active, and your muscles start to "wake up" slowly again.
<em> Read more about </em><em>NREM sleep</em><em> here:</em>
<em>brainly.com/question/14410334</em>
Answer:
A susceptible person is someone who is not vaccinated or otherwise immune or a person with a weakened immune system who has a way for the germs to enter the body. For an infection to occur, germs must enter a susceptible person’s body and invade tissues, multiply, and cause a reaction.
Answer:
Using the concept of relative dating
Explanation:
Scientists use the concept of relative dating principles to determine when the Great Oxidation event occurred.
Relative dating is the process of placing ancient event in their proper time sequence based on the relationship between rock lithologies.
- An event like the great oxidation will have significant chemical, biological and physical effect on the rock units.
- Rocks that form during this period in time will have very unique chemical signatures.
- Therefore, by studying these rocks, the age of the layer can be fixed when we compare it to the standard geological column.
