Silver is rare, durable, and malleable. it is

a gem
a precious metal
an igneous rock
a metamorphic rock

According to the big bang theory, after the "bang," the universe remained dark until about  300,000 yearsone billion yearsthree minutesthree billion years  later, when neutral atoms began to form.

Which of the following is not a symptom of desertification? a) decrease in salt content of the soil b) lowering of the water table c) reduced surface water d) increased soil erosion e) loss of native vegetation

Which of these substances does not protect against invaders in the nonspecific immune response? a. saliva b. mucus c. tears d. urine