It's 1. Melting a substance. The rest are chemical changes
Answer:
Develop systems that track and predict harmful algal blooms
Explanation:
In Massachusetts, scientists are experimenting with a sensor that can identify three types of dangerous microscopic algae by their genetic material and offer an early warning when they are detected in the water.
Matter is found every where in the universe and there is never any substance in the universe that is not composed of matter.
<h3>What is matter?</h3>
Matter is anything that has weight and occupy space. We know that matter is present in every part of the universe. Everything in the universe is composed of matter. Matter forms the basics of our study of the universe. Water, food cloths everything all are composed of matter.
The fact that matter inundates the universe has made the study of matter an unavoidable topic. As such, we can not really be able to point something that is of made up of matter. There can be no such thing!
As long as a thing does exist in the material universe, that thing is made up of matter. Look at yourself for example, matter is spread all across your body. The same occurs in the bodies of every other living thing.
The nonliving things are not also left out as they are equally composed of diverse kinds of matter that exists in the universe.
Learn more about matter:brainly.com/question/28487167
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Answer:
A. An indicator added to the solution turns green-blue.
Explanation:
A pH scale measures the concentration of hydrogen ions in acidic and alkaline solutions.
In chemistry, pH literally means the power of hydrogen ions and it is a measure of the molar concentration of hydrogen ions in a particular solution; thus, specifying the acidity, neutrality or basicity of any chemical solution.
Mathematically, the pH of a solution is given by the formula;
On a pH scale, a solution with a pH of 7 is neutral, a solution with a pH below 7 is acidic and it's basic (alkaline) when it's pH is above 7.
A pH indicator can be defined as a compound (substance) that indicates the concentration of hydrogen ions present in a solution by changing its color over a narrow range of pH values.
A pH range of 1 to 3 (1 - 3) represents a strong acid with a red color.
When an indicator added to a solution turns green-blue, it simply means that a weak base is present.
