Sustainable buildings are generally less expensive over the lifetime of the building, due to lower energy costs in production of the materials and lower energy bills. Option A is correct.
<h3>What is sustainable buildings? </h3>
Sustainable buildings refer to both a structure and the implementation of environmentally responsible and resource-efficient methods.
Sustainable buildings are generally less expensive over the lifetime of the building, due to lower energy costs in production of the materials and lower energy bills,
Hence,option A is correct.
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The kilogram is the SI unit of mass and it is the almost universally used standard mass unit. The associated SI unit of force and weight is the Newton, with 1 kilogram weighing 9.8 Newtons under standard conditions on the Earth's surface.
To find the mass of the planet we will apply the relationship of the given circumference of the planet with the given data and thus find the radius of the planet. From the kinematic equations of motion we will find the gravitational acceleration of the planet, and under the description of this value by Newton's laws the mass of the planet, that is,
The circumference of the planet is,

Under the mathematical value the radius would be



Using second equation of motion

Replacing the values given,

Rearranging and solving for 'a' we have,

Using the value of acceleration due to gravity from Newton's law we have that

Here,
r = Radius of the planet
G = Gravitational Universal constant
M = Mass of the Planet


Therefore the mass of this planet is 
Iron III ion is an iron ion with a +3 charge. If iron bonded with oxygen, it would form Fe2O3 which is rust. In this case, the oxidation number on Fe is +3 and it is -2 on oxygen. This would be called iron (III) oxide.
<span>The oxidation number of an ion times the number of the ions must equal zero when added together in a molecule with no charge. In this case, there are 2 iron molecules and each has a positive 3 charge. 2x3=6. There are three oxygen molecules each with a negative 2 charge. 3x-2=-6. 6+-6=0</span>