You are conducting an experiment on plant growth. you take a plant fresh from the soil that weighs 5 kilograms (kg). then you dry the plant overnight and determine the dry weight to be 1 kg. of this dry weight, how much would you expect to be made up of oxygen, carbon, and hydrogen?
a) 1 gramb) 4 gramsc) 40 gramsd) 960 gramse) 1 kg

The correct answer is option E.

Explanation:

Mass of fresh plant = 5 kg

Mass of plant after drying = 1 kg

The total mass of expected hydrogen, carbon and oxygen is 1 kg.

This is because when fresh plant taken out from the soil was composed of water and other organic molecules like : lipids, proteins, amino acids, carbohydrates etc.  

These all organic molecules are composed of carbon, hydrogen, oxygen, and nitrogen. On drying the plant water gets lost from the plant mass leaving behind these organic molecules to degrade.

So, we can say that the weight of dry plant is equal to the total mass of oxygen, carbon and hydrogen constituting the plant.