Answer:
<em>The correct option is cell surface markers.</em>
Explanation:
The immune cells of our body detect foreign particles and generate responses so that our body can get rid of them. The foreign particles are often termed as antigens.
The immune cells such as antibodies possess cell surface receptors which detect the foreign objects or antigens. When the cell surface receptors detect any antigen they immediately recognize that a foreign particle has invaded the body and they then identify it and start to generate response.
Answer:
It absorbs.
Explanation:
The ocean absorbs carbon dioxide from the atmosphere wherever air meets water. Wind causes waves and turbulence, giving more opportunity for the water to absorb the carbon dioxide. Fish and other animals in the ocean breathe oxygen and give off carbon dioxide (CO2), just like land animals.
If reproduction didn't exist, all species would eventually go extinct.
