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Osteoporosis results from which of the following?

A. An increase in osteocyte activity while osteoclast activity continues at expected levels

B. A decline in osteoblast activity while osteoclast activity continues at expected levels

C. An increase in osteocyte activity while osteoblast activity continues at expected levels

D. A decline in osteoclast activity while osteoblast activity continues at expected levels

Answer Explanation:

 

Osteoporosis is a condition that affects the bones, making them weak and brittle. It occurs when the balance between bone formation and bone resorption is disrupted. Bone formation is carried out by cells called osteoblasts, while bone resorption is done by cells called osteoclasts. Osteocytes are mature bone cells that maintain the bone matrix. Osteoporosis results from a decline in osteoblast activity while osteoclast activity continues at expected levels, leading to more bone loss than bone gain. This reduces the bone density and increases the risk of fractures. 

Therefore, the Correct Answer is B.

More Questions on TEAS 7 Science

  • Q #1:   The measurement indicated by the line across the center of the cell is best referred to as which of the following?

    A. Diameter

    B. Volume

    C. Area

    D. Radius

    Answer Explanation

    One way to assess the size of a cell is to measure its diameter, which is the length of a straight line that passes through the center of the cell and touches both sides. The measurement indicated by the line across the center of the cell in the diagram is best referred to as the diameter of the cell.

  • Q #2: Which of the following substances protects the skin from ultraviolet radiation?

    A. Melanin

    B. Perspiration

    C. Sebum

    D. Keratin

    Answer Explanation

    One of the functions of the skin is to protect the body from harmful effects of ultraviolet (UV) radiation. UV rays can damage the DNA of skin cells and cause mutations that may lead to skin cancer. The skin has a natural defense mechanism against UV radiation, which is the production of a pigment called melanin. Melanin is synthesized by specialized cells called melanocytes, which are located in the basal layer of the epidermis. Melanin absorbs UV rays and prevents them from reaching the deeper layers of the skin. 

  • Q #3: Hikers who found a human body at high altitude in the Italian Alps thought the man had died recently, but tests indicated he was shot with an arrow more than 5,300 years ago. Which of the following would be the best reason for prolonged preservation of the body?

    A. The food that the person ate contained toxins that killed the bacteria that would have otherwise destroyed the body.

    B. The ultraviolet rays at such a high altitude caused all the body's molecules to be preserved.

    C. The arrow wound caused blood to flow out of the body, which led the enzymes that would break down tissue to be cleared from the body.

    D. The body was frozen in the cold temperature of the Alps shortly after he died and remained frozen until it was found.

    Answer Explanation

    The answer lies in the environmental conditions of the Alps. The body was quickly frozen by the low temperature and covered by snow and ice, which prevented exposure to air, moisture, and microorganisms. The freezing also slowed down the chemical reactions that would normally break down the body's cells and tissues. Thus, the body was preserved in a natural mummy state until it was discovered by modern humans.