What is bryophytes?write any two characteristics of pteridophyts. plz

Bryophytes is a small flowerless green plant of the division Bryophyta, which comprises the mosses and liverworts.

Any two characteristics of pteridophyts are:

They are seedless, vascular plants that show true alternation of generations.

They reproduce by spores, which are developed in sporangia.

your answer is "the 1950's"

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.