Read this article about the neurons, the basic functional units of the nervous system that generate electrical signals. The signals transmit information over long distances. 

There are 3 basic functions of neurons:

The fight or flight response is an automatic physiological reaction to a physical danger, such as encountering a growling dog. The perception of threat activates the nervous system and prepares the body to fight or flee. This results in an increase in heart rate, blood pressure, and breathing rate. After the threat is gone, it takes between 20 to 60 minutes for the body to return to its pre-arousal levels.

Some people still feel the threat due to what is called phobia. A person who is terrified of heights might experience stress response if they have to go to the top floor of a skyscraper to attend a meeting. Their body might go on high alert, with their heartbeat and respiration rate increasing.

The information is taken from these resources:

Think: How is a calendar related to the succession of day and night?

Reflect: What do we use calendars for?

There are two main calendars used for indicating dates: a lunar calendar and a solar calendar. A lunar calendar is a calendar based on the monthly cycles of the Moon’s phases, whereas a solar calendar is based on the solar year, the time it takes the Earth to revolve once around the Sun. A solar year is about 365.25 days long, while a lunar month is about 29.53 days long.

Origins of the months’ names

January: Named for the Roman god Janus, protector of gates and doorways.

February: From the Latin word februa, “to cleanse.”

March: Named for the Roman god of war, Mars.

April: From the Latin word aperio, “to open (bud),” because plants begin to grow in this month.

May: From the Latin word maiores, “elders,” who were celebrated during this month.

June: From the Latin word juvenis, “young people.”

July: Named to honor Roman dictator Julius Caesar.

August: Named to honor the first Roman emperor Augustus Caesar.

September: From the Latin word septem, meaning “seven,” because it was the seventh month of the early Roman calendar.

October: Its name comes from octo, the Latin word for “eight.”

November: From the Latin word novem, “nine”

December: From the Latin word decem, “ten,”