1.  Humans are the only mammals not endowed with a natural defense against the elements, such as fur or a thick hide.

2.  Andrew Blustein of Oregon State University is looking at the possibility that some species lack a natural defense against ultraviolet radiation, making them vulnerable where ozone is depleted.

3.  Antibodies are a natural defense against disease.

4.  By making the skin soft, moist and pliable, perspiration weakens natural defenses against infectious organisms and facilitates their growth and distribution.

5.  Cancer is unregulated cell growth, and one natural defense against this is apoptosis, or programmed cell death.

6.  Drought makes the trees more susceptible to the beetle because it lowers their natural defenses.

7.  Leaves on corn plants are beginning to roll up, a natural defense by corn plants to preserve moisture.

8.  No, this floppy, gray, suction-cupped monster seems to have been born with a natural defense aimed directly at the home cook.

9.  Plants and animals evolved in isolation with few diseases or predators, so they had scant need of natural defenses.

10.  Some woods like heartwood, cedar, cypress, locust and redwood have evolved natural defenses.