C. The design would not be cost-efficient; the plane would require more fuel due to increased thrust from higher drag.
The name "flint" is often the preferred name used for material with a very fine grain size and a slightly higher luster. These "fine-grained" materials break with greater predictability and produce a sharper edge. So the middle answer
44g of CO2 can produce by the reaction of carbon with oxygen
<u>Answer: </u>The correct statement is X is the effective nuclear charge, and it increases across a period.
<u>Explanation:</u>
We are given that:
X = number of protons − number of core electrons
Effective nuclear charge is defined as the actual nuclear charge (Z = number of protons) minus the screening effect caused by the electrons present between nucleus and valence electrons. These electrons are the core electrons.
The formula used for the calculation of effective nuclear charge given by Slater is:

where,
= effective nuclear charge
Z = atomic number or actual nuclear charge or number of protons
= Screening constant
The effective nuclear charge increases as we go from left to right in a period because nuclear charge increases with no effective increase in screening constant.
Hence, the correct answer is X is the effective nuclear charge, and it increases across a period.