21 is the most common needle gauge used for routine venipuncture. This gauge needle is used to draw blood for testing.
What isn't a sign of Attention-deficit/hyperactivity disorder nor ADHD would be washing hands when they are already clean - C. this sounds more like a symptom someone who has OCD would exhibit. Such people tend to exhibit symptoms that are similar to what you wrote more often.
Answer: Option A
Explanation:
The sleep and wake cycle involves only one hormone named melatonin, whose detectable level is found in the blood during night time.
The area that is responsible for controlling the sleep wake cycle includes multiple parts of the brain which work in coordination with each other.
These areas include thalamus, pons and hypothalamus which regulates the sleep wake cycle.
Hence, the correct answer is option A
Some of the reasons can be:
If you're a pre-teen or a teenager who has only started menstruating, you may find that it takes a while for your period to settle in and become regular.
I couldn't think of anything else, but hope this helped enough!
To find the best answer, ask your mom!
~Aurora