At how many locations in humans have scientists identified the occurrence of single-base $DNA$ differences?

What was used as a host in the $HGP$?

Which of the following is not associated with the $HGP$?

In addition to the human genome sequence,draft or finished genome sequences existed for eight model organisms by $2002$. Which of the following organisms are not the part of that group of eight model organisms?

Provide the full forms of the following abbreviations:
$1.$ $\text{YAC}$
$2.$ $\text{SNPs}$
$3.$ $\text{VNTR}$
$4.$ $\text{PCR}$

Give an account of the methods used in sequencing the human genome.