Questions

Here in the given options, Gold is a malleable substance.

Malleable substance means a metal or a material able to be hammered or pressed into shape without breaking or cracking. i.e, tensile.

The olfactory system is the only system in which the receptors send their signal directly to the higher brain and bypass the thalamus, which normally acts as a filter for the processes of the lower brain.

Materials that allow electricity to flow are called electrical conductors and that materials which does not allow electricity to flow are called Insulators.

Ionic bonding is the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion.

Hence, when Ionic bonds are formed metallic atoms tend to lose electrons and become positive ions

Here Soda is a Heterogenous Mixture.

A Heterogeneous Mixture is a mixture having a non-uniform composition i.e, the mixture contains components in different phases. Using various means, the parts in the mixture can be separated from one another.

Progeria is a rare genetic disordr which involves symptoms resembloing aspects of aging, manifested at a very early age.
The term is often used in reference to Hutchinson - gilford progeria syndrome(HGPS).