Questions

Hierarchy is a system of ranking in which members of a particular society are ranked in an ascending order depending on various factors.

Hence, the term hierarchy refers to a power structure in which each member knows his or her own place.

One way is shorting the two inputs of the NAND gate and passing the input.

truth table:

A B output

1 1 0

0 0 1

The second way is passing the input to only one input (say A) of the NAND gate. Since the other input  (say B is floating, it is always logic one.

Truth table:

A B output

1 1 0 

0 1 1

The shortest gestation period known is 12 to 13 days, shared by three marsupials: the American or Virginian opossum (Didelphis marsupialis); the rare water opossum, or yapok (Chironectes minimus) of central and northern South America; and the eastern native cat (Dasyurus viverrinus) of Australia.

Gestation is the period of time between fertilization and birth in oviparous animals.

The elephant has the longest gestation period of about 23 months of any land animal.