Which substance could most easily cross a synthetic membrane composed of phospholipids but not proteins

The table shows dates and appearance of index fossils. which rock layers can be dated most precisely? a) a layer containing both a fossil 4 and a fossil 3 b) a layer containing both a fossil 2 and a fossil 3 c) a layer containing both a fossil 1 and a fossil 4 d) a layer containing both a fossil 1 and a fossil 2

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

Which feature of a human community is similar to a niche in a biological community