The energy pyramid describes decomposers compared to energy lost as heat. Primary producers start at 100% and it decreases to 10% at primary consumers, 1% at secondary, .1% at third level, and .01% at apex.
The biomass pyramid describes the total mass of an organism and as a biomass moves up, the overall mass is losing volume. This means it decreases as it moves from the bottom to the top.
<span>The important function of cells in the eyes involve vision. This is the function of the choroid that contains pigment cells that absorbs light to prevent reflection that could impair vision. The retina, the innermost layer of the eye contains the light sensitive cells called rods and cones. </span>
If the cornea were to work alone, the image formed would be blurred as the point of image formation would be behind the retina. Therefore, with the help of the lens in the eye, the focal length is reduced to 1.7 cm so that the image forms on the retina.
Answer : The correct option is, (1) an atom with 20 protons, 21 neutrons, and 20 electrons.
Explanation :
Isotope : It is defined as the element that have the same number of protons but have the different number of neutrons of each of the atom.
Atomic number is defined as the number of protons or number of electrons.
Atomic number of = number of protons = number of electrons
Mass number is defined as the sum of number of protons and number of neutrons.
Number of neutrons = Mass number - Number of protons
As we are given,
Element = Calcium
Number of protons = 20
Number of electrons = 20
Number of neutrons = 20
For the isotope of calcium, the element should have the same number of protons but the different number of neutrons of each of the atom.
From this we conclude that, the option (1) would be an isotope of calcium because in this the protons and electrons are same but neutrons are different.
Hence, the correct option is, (1) an atom with 20 protons, 21 neutrons, and 20 electrons.