Which of the following contributes most directly to the hardness of bones? 1) hydroxyapatite 2) periosteum 3) articular cartilage 4) osteoid

The correct option is number 1. Hydroxyapatite contributes most directly to the hardness of bones

Explanation:

Hydroxyapatite can be described as a naturally occurring biological molecule of high importance. It provides hardness the bones and teeth. Hence, option 1 is correct.

Periosteum can be defined as the outer layer of a bone which functions as an attachment site for the skeletal muscles. Osteoid is a structure that is made before a bone occurs in its mature form. Hence all the other options 2, 3 and 4 are false.

humans can cause extinction of a species through overharvesting, pollution, habitat destruction, introduction of invasive species (such as new predators and food competitors), overhunting, and other influences. explosive, unsustainable human population growth is an essential cause of the extinction crisis.

explanation:

i didn't have the answer choices , but i tried my best.