Practice MCQ Questions and answers on Biology-GK

Stomata are tiny, microscopic pores that critical for photosynthesis.

The photosynthesis occurs in the day.

During the process of photosynthesis, green plants and some other organisms use sunlight to convert carbon dioxide (CO₂) and water (H₂O) into glucose (a type of sugar) and oxygen (O₂). This process takes place in the chloroplasts of plant cells and is represented by the following chemical equation:

6 CO₂ + 6 H₂O + light energy → C₆H₁₂O₆ + 6 O₂

As you can see, the oxygen released during photosynthesis comes from the water molecule (H₂O). Carbon dioxide (CO₂) is used to produce glucose (C₆H₁₂O₆), which serves as an energy source for the plant. So, the correct answer is Option A: H₂O.

In plants, the process of photosynthesis takes place in the mesophyll of the leaves, inside the chloroplasts. Chloroplasts contain disc-shaped structures called thylakoids, which contain the pigment chlorophyll.

Photosynthetic cells contain special pigments that absorb light energy. Different pigments respond to different wavelengths of visible light. Chlorophyll, the primary pigment used in photosynthesis, reflects green light and absorbs red and blue light most strongly.

In plants, photosynthesis takes place in chloroplasts, which contain the chlorophyll. Chloroplasts are surrounded by a double membrane and contain a third inner membrane, called the thylakoid membrane, that forms long folds within the organelle.

If air is polluted with sulphur dioxide, then lichens will die in that particular environment. Since the era of industrialization, many species of lichens have gone extinct. Due to this property, lichens are considered to be the indicators of the air pollution.

Food wrapped in newspaper is likely to get contaminated with lead.

BOD stands for a measurement that tells us how much oxygen is needed by bacteria to break down organic matter in a water sample. Think of it like this: If there's lots of decaying plants or waste in the water, bacteria will need more oxygen to eat it all up.

Let's look at the options:

Option A: Biological Oxygen Deficit - This sounds close, but "deficit" means a shortage. BOD measures the amount of oxygen needed, not a shortage.

Option B: Biological Oxygen Difference - This doesn't really make sense in this context. We are measuring the oxygen needed for a specific process.

Option C: Biological Oxygen Demand - This is the correct answer! It perfectly describes the measurement of oxygen needed by bacteria to decompose organic material in water.

Option D: Biological Oxygen Distribution - This describes how oxygen is spread in the water, not the amount needed for decomposition.

Therefore, the full form of BOD is Biological Oxygen Demand.

The non-biotic pollutant of underground water is arsenic.