The correct answer is: Eubacteria.
The human microbiota is the name for all of the bacteria found within the human body. This aggregates of microorganisms are wide spread in different tissues, such as the skin, mammary glands, seminal fluid, uterus, saliva, oral mucosa, conjunctiva, gastrointestinal tracts.
The statement above is false. The blood levels of calcium is regulated by parathyroid hormone.When one is not getting adequate calcium in one's diet and the blood level of calcium is low, the parathyroid hormone will be released. The parathyroid hormone can increase the blood calcium in several ways:
1. by stimulating osteoclasts which break down bone and release calcium into the blood stream.
2. by increasing the amount of calcium re-absorbed by the kidney before it can be excreted in urine.
3. by triggering the formation of calcitriol which increases the absorption of dietary calcium at the intestines.
it is a.cell because tissues, organs and organisms are larger than a cell so 'a' is the correct answer