Explain why the sickle cell mutation is selected for in certain areas of the world

Compare and contrast the relative importance of the sporophyte vs gametophyte generation between nonvascular plants (bryophytes), seedless vascular plants and seed plants, and explain the ecological significance of a larger sporophyte generation

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

Which statement correctly compares metaphase i and metaphase ii? in metaphase ii twice as many chromosomes line up along the middle of the cell as in metaphase i. in metaphase i twice as many chromosomes line up along the middle of the cell as in metaphase ii. in metaphase ii twice as many chromosomes are pulled to opposite ends of the cell as in metaphase i. in metaphase i twice as many chromosomes are pulled to opposite ends of the cell as in metaphase ii.