Who specializes in treatment of diseases of the rectum and anus?

In general, characteristics that an organism survive and reproduce become more common over time. what mechanism of evolution causes this?

Cattle with brown fur and cattle with white fur will produce a reddish roan calf . when examined closely, the calf show about an even number of brown hairs and white hairs that give a reddish appearance when viewed from far away. the fact that both the brown fur allele and the white fur allele are expressed equally in the offspring is an example of

Explain how mendel kept his pea plant from self pollination