<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>
I believe it is D, all of these. :) I hope this helps! Please tell me if I'm wrong :)
Answer:
Green algae is divided into chlorophyte and chlorophyte. It possess chlorophyll a and b.
Bryophytes includes the liverworts, mosses and hornworts. It is know tracheaophytes I.e. is not vascular without extensive transport system, it needs water to reproduce sexually. It's Gametophyte is dominant and stomata are absent. (Hornworts possess stomata; it's related to tracheaophytes.
Ferns have vascular tissue, xylem and pholem, stem, root, leaves, dominant sporophyte. It's sporophyte possess rhizomes and fronds plus sporingia aldo called sori. Ferns are seedless vascular plants.
Gymnosperms includes the conifers, cycad e.t.c. It has its ovules resting on a scale. The ovules later develop into the seed. These seeds are naked as there are not enclosed in the chambers.
Angiosperms have flowers and fruits and show diuble fertilization. This is a huge clade that consists of all flowering plants. Unlike Gymnosperms
They develop enclosed in chambers known as ovaries.
Answer:
Water is a covalent compound.
Explanation:
covalent compounds are individual molecules characterized by the sharing of electrons between two or more atoms. Two atoms with similar electronegativity will not exchange an electron from their outermost shell; the atoms instead share electrons so that their valence electron shell is filled.
Example:
Examples of compounds that contain only covalent bonds are methane (CH4), carbon monoxide (CO), Water (H2O) and iodine monobromide (IBr).
Properties:
1. At room temperature and normal atmospheric pressure, covalent compounds may exist as a solid, a liquid, or a gas.
2. Covalent compounds do not exhibit any electrical conductivity, either in pure form or when dissolved in water.
3. Covalent compounds have lower melting and boiling points.
Histone deacetylase is responsible for removing the acetyl group from the histone 3 lysine 9 residue. Remember that deacetylation is one step in converting euchromatin to heterochromatin. Because euchromatin is transcriptionally active (transcriptional machinery is able to reach gene of interest), and blocking histone deacetylase activity would result in an the DNA remaining as euchromatin, we would expect to see an increase in transcriptional activity.
So there’s your answer: An increase in transcriptional activity.
