I' m going to say B. WHAT SUBSTANCES MAKE UP AN EGGSHELL?
You have to look at keywords here, and the only one that refers to scientific research would be Substance.
Answer:
Explanation:
Notation
represent the tensile strength for the Kevlar 49 fibers
represent the tensile strength for the epoxy resin
79% by volume is made of Kevlar 49 fibers
The rest 100-79=21% is made of epoxy resin
Tensile strength is a "measurement of the force required to pull something such as rope, wire, or a structural beam to the point where it breaks". Can be defined as "the maximum amount of tensile stress that it can take before failure".
For this case we need to use a basis of calculus since we don't know the total volume but we can assume a reference value on order to make the calculations.
If we assume a total volume of 
we can do the follwoing balance:
We can replace the values given:
So then the strength of the composite material is :
The Mantle lies underneath the crust.
Answer:
4) Isaac Newton was the first scientist to propose the idea that gravity increases distance between objects decrease
Explanation:
1 - Kepler may have inspired most of Newton's propositions, but there is no record of collaborating on the theory of universal gravitation.
2 - The universal gravitation theory resemble the works of other great scientists, but Newton was indeed the first to propose this idea of gravitation
3 - On the contrary, these scientists have shared concepts, with differences in accuracy that supersede each other to be accepted by the community (i.e: Einstein being at the forefront despite sharing some ideas with Newton)
