1. The copper was the first (metal used) by humans and is second (only) to iron (into) its utility of through (the ages).

2.The leopard seal is the only pinniped ____ preys on penguins and other seals.
A that normally B. of which it normally C. normally D. that it normally

3.Located at the upper end of each ___ an adrenal gland, and integral part of the endocrine system.
A. kidney which is B. kidney is C. kidney being D. kidney