Which hydrocarbon is saturated?
(1) propene (3) butene(2) ethyne (4) heptane

The answer is (4) heptane. Saturated hydrocarbon means that there is no double bonds between the carbon atoms. For propene and butene, there is double bond. For ethyne, there is triple bond.

The use of piers and beams to build a strong foundation for a house.

The  grandmother cell  is a hypothetical  neuronthat represents a complex but specific concept or object.[1]  it activates when a person "sees, hears, or otherwise sensibly discriminates"[2]  a specific entity, such as his or her grandmother. the term was in use at least as early as 1966 amongst staff and students in the department of experimental psychology, university of cambridge, england. a similar concept, that of the  gnostic neuron, was proposed two years later