Can the "which" be left out?

(1) I think "which" could not be left out in " Welcome to the White House (which) provides its millions of visitors with an array of useful information". What do you think?

Context:
As one of the most popular web sites on the Internet, Welcome to the White House provides its millions of visitors with an array of useful information, including facts about the Presidency, the history of the White House, a record of our nation's progress, a special children's site, and access to agencies and services throughout the federal government.

(2) What does "drawn" mean?

Context:
John Harris, a member of the Human Genetics Commission, told a meeting at Westminster he did not see any distinction between aborting a fully grown unborn baby at 40 weeks and killing a child after it had been born.

Harris, who is a professor of bioethics at Manchester University, would not be drawn on which defects or problems might be used as grounds for ending a baby's life, or how old a child might be while it could still be destroyed.