From the List Below, the Best Example of a Positive

question 173

Multiple Choice

From the list below, the best example of a positive externality is

• A)forbidding the use of cell phones in public
• B)planting trees along the pavement, which adds beauty and creates shade
• C)banning the sale of candy in elementary schools
• D)prohibiting street parking in all residential neighbourhoods

---

Definitions:

Osteoblast

Bone-forming cell.

Hydroxyapatite

A naturally occurring mineral form of calcium apatite, mainly found in bones and teeth, providing hardness and strength.

Osteocyte

Mature bone cell surrounded by bone matrix.

Bone Maintenance

The process by which bone tissue is renewed through the activities of osteoclasts (breaking down bone) and osteoblasts (forming new bone), ensuring strength and health of bones.