Which is not characteristic of primitive mammals

C, h, o - elements that are common to biomolecules. if the biomolecule in question is a protein these elements also combine with nitrogen. which molecule below is a protein?

Astudent observes a star from two positions of earth in its orbit, in summer and winter, and measures the change in the position of the star. which of these can be best calculated by this method?

How does secondary succession differ from primary succession?