PPSC MCQs

Microorganisms use sugars during fermentation.
The process is used in bread, yogurt, and other foods.

In graphite, each carbon forms three bonds and leaves mobile electrons.
These electrons carry charge along the layers.

Yeast ferments sugars and releases carbon dioxide.
Gas bubbles expand within the dough.

Diamond and graphite are allotropes of carbon.
Their different structures give very different properties.

Lactic-acid bacteria ferment milk sugar.
The acid causes proteins to thicken and gives yogurt its sour taste.

Each carbon atom bonds strongly to four others in diamond.
The rigid network resists deformation.

Pasteurization heats food or drink for a specified time.
It improves safety while limiting quality changes.

Polymers consist of repeating monomer units.
Many plastics, fibers, and biological molecules are polymers.

Many foodborne bacteria grow quickly at warm temperatures.
Prompt refrigeration reduces the risk.

Strong polymer structures can resist decomposition.
This durability is useful but creates waste-management problems.

Cells are the smallest units capable of carrying out life processes.
All living organisms consist of one or more cells.

Natural gas consists mainly of methane.
It burns relatively cleanly compared with coal.