Questions

A Shrimps heart is located on its head.

Plantain plant is a herb, because it does not have an aerial stem - what appears as a stem is really the leaves with sheathing bases. As the piant lives for several years it is called perennial herb

Steel is not a compound or element. Steel is an alloy of iron and carbon and other elements and hence it is a mixture. Because of its high tensile strength and low cost, it is a major component used in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons.

Sound is a mechanical vibration and needs a medium for propagation. The higher the density of the medium, the faster the sound travels. So, sound cannot travel through vacuum.

As the sound travels faster in solids than liquids and gases, sound travels faster in the glass than Air and water.

The four bonds of carbon tetrachloride (CCl4) are polar, but the molecule is nonpolar because the bond polarity is cancelled by the symmetric tetrahedral shape. Hence, making the net dipole as zero and molecule as non-polar.

When other atoms substitute for some of the Cl atoms, the symmetry is broken and the molecule becomes polar.

Scope, quality, and cost are the triple constraints. Quality is a function of these three areas and can impact them; however it is not considered one of the components of the triple constraint. Therefore, Answer A, B, and C are incorect.

A greenhouse gas is a gas in an atmosphere that absorbs and emits radiant energy within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. 

Carbon dioxide is a main greenhouse gas, found in car exhaust pipes.
Methane and nitrous oxide is another type of greenhouse gas.

Oxygen is the only clean gas out there because we need it to survive. Therefore, the only gas that is not a greenhouse gas is Oxygen.