Their valency is one and both belong to the third period
<h2>Permanent tissues in Plant</h2>
Explanation:
A) The cell walls of parenchyma cells are thinner than those of sclerenchyma cells
Plants posses basically two kinds of tissue- meristematic tissue and permanent tissue.
Meristematic tissue is made up of cells which are capable of active division and give rise to other tissues,.
Permanent tissue are already differentiated and usually do not divide.
Permanent tissues are -collenchyma, sclerenchyma and parenchyma.
Parenchyma and collenchyma are living whereas sclerenchyma is non-living.
Fossils only form if certain qualifications are met, and some organisms cannot meet them, so they just cease to exist, not a single sign of them. This could happen if they were organisms that decayed completely. Fossilization can include freezing, drying, and encasement, usually in tar or resin.