Answer:
c
Explanation:
Random distribution of the Isopods should be 50/50 in A and B.
Chi-square = 
where O = observed frequency and E = expected frequency
Chamber O E Chi-square
A 18 10 
= 6.4
B 2 10 
= 6.4
<em>Total Chi-square </em>= 6.4 + 6.4 = 12.8
<em>Degree of freedom</em> = 2 - 1 = 1
<em>Tabulated Chi-square</em> (α = 0.05) = 3.8415
The calculated Chi-square exceeds the critical value, hence, it is significant and not due to random.
<em>The correct option is </em><em>c</em><em>.</em>
The sympathetic nervous system is a part of the autonomic nervous system that carries stress responses or "flight or flight" responses that involves feelings of rush. The activation of sympathetic nervous system therefore increases the heart rate. The parasympathetic nervous system is another part of the autonomic nervous system which is responsible for "rest and digest" responses that involves feelings of relaxation. The activation of the parasympathetic nervous system decreases the heart rate.
C because ye ye ye ye ye ye ye
Answer:
d. Fluoride becomes incorporated into the crystalline structure of teeth, making them less susceptible to decay
Explanation:
Dental caries results when cariogenic (caries-causing) bacteria metabolize carbohydrates or sugars present in the mouth for their energy needs, producing organic acids as byproducts, thus lowering the pH of the plaque biofilm.
The hydroxyapatite of tooth enamel is composed mainly of phosphate ions (PO₄³⁻) and calcium ions (Ca⁺). Under normal conditions, there is a stable equilibrium between the calcium and phosphate ions in saliva and the crystalline hydroxyapatite. At low pH (acidic conditions), there is a shift in equilibrium resulting in the dissolution of hydroxyapatite from tooth enamel, a process known as demineralization. A reverse process called remineralization (the process of incorporation of minerals in tooth enamel) occurs when the saliva, acting as a buffer elevates pH. When equilibrium is shifted to favor continued demineralization, dental caries results.
However, when fluoride is present in saliva, fluorapatite, rather than hydroxyapatite, forms during the remineralization process as fluoride ions replace hydroxyl groups in the formation of the apatite crystal lattice.
Fluorapatite is less soluble than hydroxyapatite making it more resistant to demineralization, even under conditions of low pH. Thus, fluoride acts as an effective anticaries agent.
