Answer:
The main purpose of the circulatory system is to transport blood, oxygen, nutrients and hormones to and from different cells and tissues throughout the body.
Explanation:
This system works hand-in-hand with the respiratory system to facilitate the exchange of oxygen and carbon dioxide within the blood per the alveoli in the lungs.
The warning has given us the tornado's VELOCITY, since it gave us both the speed and direction.
Answer:
Wavelength of light is 750 nm.
Explanation:
It is given that,
Frequency of light, 
The relationship between the wavelength and the frequency of light is given by :
Where
c = speed of light
= frequency of light
= wavelength of light
Hence, the correct option is (d) "750 nm".
Answer: emission of electromagnetic radiation
Explanation:
When an atom is in its <u>ground state</u>, its electrons fill the lower energy orbitals completely before they begin to occupy higher energy orbitals.
On the other hand, when an atom is <u>excited (</u>it has left its ground state, in which each electron occupies its place in its orbit, around the nucleus), some electron jumps out of the orbit it occupied in its fundamental state to an outer orbit, further away from the nucleus and then return to the ground state, emitting in the form of electromagnetic radiation (light which may be visible or not) the energy received.
So, when an excited electron passes from an outer orbit to the ground state, it produces electromagnetic radiation of a specific wavelength that depends on the amount of energy the electron releases in the process.
Therefore:
<h3>
The change of an atom from the excited state to the ground state always requires <u>
the emission of electromagnetic radiation.</u></h3>
