Answer:
oxygen
Explanation:
oxygen is an essential nutrient which the body needs especially during respiration.
it help the blood cells do provide energy.
without oxygen, there is no gaseous exchange
Because an antibody is "made" relative to the antigen, but kept at low levels when you are exposed the first time ("primary immune response"). The second time you're exposed to the same antigen, memory cells recognize it and the body produces a high level of antibodies, and the level of antibodies usually remains higher for a longer time ("secondary immune response"). This is your basic immune response (primary and secondary).
This explains exactly why vaccines are effective to extremely effective.
The sun.........................................................
A chemical defense mechanism is called bioluminescence.
As mentioned in the reaction, Ceratium fusus undergoes a special chemical reaction at night which helps them defend themselves from predators. During this reaction, light is produced inside a living organism. However, this type of reaction does not produce heat although it does produce light.
<h3>
What is bioluminescence used for?</h3>
The most well-known purpose of bioluminescence is to defend the organism against attacks by predators. This is because the light confuses or frightens predators.
Besides confusing the predator, the light can also alert large predators to approach the location of the organism, in this way this large predator will eat the predator that is threatening the organism which in our question, is Ceratium fusus.
Many marine organisms use the phenomenon of bioluminescence for their defense, in particular marine invertebrates, vertebrates, certain micro-organisms as well as certain fish and fungi.
Hence concluded that the bioluminescence characteristic of Ceratium fusus is being described.
To know more about bioluminescence refer to the link :
brainly.com/question/765632
