The statement about ADHD that is true is: "ADHD has no clear physical symptoms that can be detected via an x-ray or blood test"
<h3>What is ADHD?</h3>
This is an acronym for a kind of mental disorder that is called Attention Deficit Hyperactivity Disorder (ADHD).
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental psychiatric condition.
It is characterized by challenges concentration, excessive activity, or difficulty restraining behavior that is inappropriate for a man's age.
Learn more about ADHD at;
brainly.com/question/10002219
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The correct answer is - the first, black layer.
If the situation is that the rock layers have not been disturbed, and their alignment is in order as the periods in which they have been on the top, before being covered with new sediments, than the oldest fossils will be at the bottom layers, will the newest in the top layers.
In this situation, we know that the mollusks have evolved before the arthropods, and since the arthropods are found in the second, grey layer, the mollusks will be found in the layer bellow them, the first, black, layer.
