Yeast is the organism, which is added to the dairy products to increase their volume. When the yeast cells multiply, they breathe and release carbon dioxide, which causes an increase in the volume of food products. 

The causal organism is bacteria.

Polio, chicken pox, and influenza are the diseases for which the causal organism is virus, whereas malaria is an example of a bacterial disease. 

Antibiotics are the preparation made from modified bacteria, which act against any bacterial infection, whereas, pathogen refers to the disease causing organisms. Carrier organisms transmit disease from a diseased person to a healthy one and invaders refer to any organisms, which enter into our body irrespective of the fact whether it is useful or harmful. 

Yeast cells undergo anaerobic respiration and convert the grape sugar into alcohol. The process is known as fermentation. Also, they are used in baking industry to raise the volume of the products, but cheese preparation does not need an action of yeast.

Microorganisms are such a group of organisms which are omni-present, from oceans to deserts, from -25^oC to +25^oC, inside human body or in the air.

Diabetes is the disease for which no microbe is responsible but is caused due to the improper functioning of a particular body organ. Therefore, it can't be cured by vaccine. 

Antibiotics are the substances that destroy or inhibit the growth of harmful microorganisms, whereas, pathogen refers to a disease causing organism. Vaccine refers to a biological preparation, which is made from modified viruses or bacteria to induce immunity in human beings, and antibodies are present in the blood and helps fighting against infections. 

During curd formation, milk, sugar and lactose are converted into lactic acid by the action of the bacteria lactobacillus, thereby making curd taste sour.

Bacteria do not decompose non-biodegradable wastes.

Female Aedes mosquito acts as a carrier of dengue.

Multicellular algae generally live in two forms, either isolated or in colonies. Volvox is the only example of multicellular algae out of the given four, which lives by forming colonies whereas the other three stay isolated.