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The mass ratio of potassium and selenium in the given compound is equal to 1 : 2.

What is the mass ratio?

The mass ratio also known as the percent composition by mass defines the proportion of a particular compound that consists of the constituent elements of that compound.

The percent composition by mass of a constituent element of a compound can be determined by the division of the mass of that element by the molar mass of the compound, followed by its multiplication by 100.

According to the law of constant proportion, a pure compound is always made up of the same elements combined together in a fixed proportion by weight.

Given the mass of the potassium (K) in the compound = 39 g

The mass of selenium (Se) in the compound  = 78

The mass ratio of K  and Se is 39 : 78

The simplest form of the ratio of potassium and selenium is 1 : 2.

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Answer;

Surface fire

Explanation;

• Surface fires are type of forest fires that may burn primarily as a surface fire, spreading along the ground as the surface litter and undergrowth on the forest floor and is engulfed by the spreading flames.
• They are the easiest fires to put out and cause the least damage to the forest. Surface fires create the least amount of destruction.
• These fires protects the forest by releasing the nutrients that would otherwise decompose slowly, having little benefit to the ecosystem.
• Additionally, these fires allow more open spaces for new and different kinds of vegetation to grow and receive sunlight.