1. ALGAE is an aquatic organisms which conduct photosynthesis on its own for its survival. For eg: Seaweed

They are of two types unicellular algae ( eg. Diatoms, protozoa) and multicellular algae (eg. Red algae, brown algae).

2. BACTERIA is an micro organism which cannot be seen through naked eye. It is visible through microscope. They are harmful and useful bacteria. Harmful bacteria can cause infection and useful bacteria are used for fermentation. There are 5 types of bacteria.

• Spherical shaped ( cocci)
• Rod shaped ( bacilli)
• Spiral ( spirilla)
• Comma shaped
• Corkscrew shaped.

Hope this helps you

All the best