What are the two types of pure substanes?

What are the two types of charges?

What are the two types of fibres found in the connective tissue? Mention their functions.

What are the main two types of transformer.

What is a junction transistor. What are the different types of transistors? Show their schematic representation.

What are the types of arrangment of units in different plastics?

Name the two types of proteins secreted by fibroblasts.

What are the different types of RNA found in the cell?