Can iron-deficiency provide natural immunity against parasites?

Hurry which of these is true about index fossils? a) are very scarcely found b) used as guides in relative dating c) found in the youngest layer of the rock d) used as reference points in absolute dating

What does the hardy-weinberg principle relate to? a. chances of survival of an organism b. frequency of alleles in a population c. natural selection in a species d. causes of evolution among organisms

This is so important ugh its 25 points