A fibre which contains simple pits is
Fibre tracheid
Textile fibre
Libriform fibre
Bast fibre
$A$. According to Clowes root apex consists of an inverted cup like structure.
$B$. Low amount of $RNA$, $DNA$ and protein is characteristic of waiting meristem.
$C$. Cells of reserve meristem can divide only when the root apex gets injured.
Meristematic tissue responsible for increase in girth of tree trunk is