D. fingernails
Skin, hair, and vertebrae are all the outer layer of the body and protect the body. The fingernails aren't part of that.
Abscission layer is the layer of cutinized parenchyma cells that develops in the abscission zone. The abscission zone form across the base of the plant part, where the break eventually occurs. During the photosyntesis chlorophyll using sunlight produces sugar and storches which are used as food by plant. And sugar accumulate in leaves.
Answer:
The model appears to show the carbon dioxide molecules entering the blood cell and the oxygen molecules existing the cell.
Answer:
Variations Within Ecosystems
Ecosystem diversity can be described as a term which is used o describe the changes within an ecosystem and the impact these changes have on the environment and humans.
Variations within an ecosystem can cause genetic drifts. Variations will cause those organisms to survive which are better adapted to survive to the changes which occur in an ecosystem. And the organisms which are not better suited become extinct over a period of time. Hence, this will lead to a wide rise in biodiversity.
<span>The horizontal line present across the front teeth are called perikymata. These are incremental growth lines that appear on the surface of tooth enamel as a series of linear grooves. These lines can be used to assess how long the crown of the teeth formed. </span>