Granting permission to users on different schema in Oracle

In Oracle,Granting privileges for objects to users in schema A to users of schema B,

1) User in Schema A should have DBA role or "WITH GRANT " privileges for providing access to user of schema B.

2) From System/Sys login,can't provide objects privileges to user of Schema A to B and vise versa.

"With Grant" option:

• Only for object privileges, not system privileges.
• Only the person who granted the privilege can revoke the privilege.
• Revoked privileges can "cascade", allowing the first grantor to revoke many subsequent grants.