I think it would be the sclereids cells
Oxygen enters the blood in the A. Bronchi.
Polystyrene is a good insulator as it has small air bubbles trapped inside of it. This means heat energy cannot flow through them therefore it is an effective material for keeping honeybees warm in the winter. Hope this helps :)
Okay so there are two types of ERs, smooth and rough.
Rough endoplasmic reticulum contain ribosomes on the outer surface. It provides large surface area for proteinsynthesis and the synthesis of glycoproteins and also provides a pathway for the transport of materials.
Smooth ER synthesises, stores and transports lipids and carbohydrates.
Hope this helps