It is an upper-middle income country
Copper sulfate and water will be the chemical species that were left in the beaker.
The inorganic material known as copper sulfate is created when sulfur and copper are mixed. It has the power to destroy roots, plants, algae, fungi, and snails. The level of hazard in copper sulfate depends on the amount of copper. In the US, the use of copper sulfate in pesticide products has been permitted since 1956.
Sulfuric acid, also known as sulphuric acid or oil of vitriol in the past, is a mineral acid made up of the elements hydrogen, oxygen, and sulfur with the chemical formula H₂SO₄. It is a viscous liquid that is miscible with water. It has no color or smell.
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<em>Answer:</em>
<em>variable-interval </em>
<em>Explanation:</em>
<em>In psychology,</em><em> a variable-interval schedule is described as a schedule of reinforcement which is considered as one of the parts in the operant conditioning and was discovered by </em><em>B. F. Skinner. </em><em>It is also denoted as VI, and is defined as a process whereby "reinforcement" is being given to a specific response only after a well-defined amount of time has been passed i.e, unpredictable time and therefore the amount of time is supposed to be on a variable or changing schedule.</em>
<em>As per the question, studying for professor Wallace's surprise quizzes will be reinforced on a variable-interval schedule.</em>
