They have a spine
hope it helps
<span>The immune system is the body's natural defense mechanism against organisms that can cause infection.There are three types of mechanisms:
1. Cellular :</span><span> refers to the recognition and/or killing of virus and virus-infected cells by leukocytes and the production of different soluble factors (cytokines) by these cells when stimulated by virus or virus-infected cells
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2. Structural: </span>barriers and the immune system defend the body<span> against organisms that can cause infection. </span>Natural<span> barriers include the skin, mucous membranes, tears, earwax, mucus, and stomach acid.
3. Chemical: </span><span>Some of these include the low pH of the stomach, which inhibits the growth of pathogens; blood proteins that bind and disrupt bacterial cell membranes; and the process of urination, which flushes pathogens from the urinary tract.
</span><span>antibodies - chemical
tissues lining hollow organs - cellular
phagocytes - cellular
skin - structural
antigen - chemical
leukocytes - cellular</span>
Distance is a scalar quantity that refers to "how much ground an object has covered" during its motion.
<span>Displacement is a vector quantity that refers to "how far out of place an object is"; it is the object's overall change in position.
Hope this helps!</span>
Answer:
Usually considered algae, dinoflagellates are mostly marine plankton, but they also are common in freshwater habitats. Their populations are distributed depending on sea surface temperature, salinity, or depth.
Explanation:
The nutrients from the soil is taken up by the roots
to be distributed to the entire plant. The plant absorbs the nutrients into its
cells and utilized by the leaves, stem, trunk. They are also used to grow
flowers and to bare fruits.
Moreover, the nutrients are divided into two groups;
first the macronutrients which is needed by the plants in large amount such as
nitrogen, phosphorus, potassium, calcium, magnesium and sulfur. Second group is
the micronutrients, needed in tiny amounts that include zinc, copper,
manganese, boron, iron, sodium and cobalt. These two groups are essential for
normal plant growth and development.
