Bryophytes are known as non-vascular plants. what makes them . non-vascular? choices: . absence of xylem and phloem. . inactive xylem and phloem. . active xylem but inactive phloem.

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