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zepelin [54]
3 years ago
8

Where do scientist believe that homo sapiens sapiens first appeared between 150000 and 200000 years ago?

Biology
1 answer:
8_murik_8 [283]3 years ago
5 0
Homo sapiens means wise human being, it one of several species grouped into the genus Homo, but it is the only one that is not extinct. It is the specie where all human beings belong. They replaced Neanderthals during 30,000 BC. Scientists believe that Homo sapiens appeared in Africa between 150,000 and 200,000 years ago.
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What role do receptor sites play in drug activity? What role do receptor sites play in drug activity? The receptor site removes
KATRIN_1 [288]

Answer: The receptor site is the location that a drug binds to, altering the function of a biomolecule.

Explanation:

The drug receptors site, are the sites where the sites where the drug molecules bind.  Basically, a low number of receptors exists and the extent to which the molecules occupy their sites differ with the concentration of drug.  The receptor site changes the conformation and function of the binding molecule of the drug.

5 0
2 years ago
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The highlighted structure contains contributions from which cord(s) of the brachial plexus? lateral cord only medial and lateral
Makovka662 [10]

Highlighted structure is median nerve cord only.

It originates from brachial plexus from medial and lateral cords. Lateral wire best medial and lateral cords lateral and posterior cords medial cord handiest.

The medial twine is the a part of the brachial plexus fashioned with the aid of of the anterior department of the lower trunk (C8-T1). Its name comes from it being medial to the axillary artery as it passes through the axilla. the opposite cords of the brachial plexus are the posterior cord and lateral cord.

The lateral cord gives rise to the lateral pectoral nerve. The posterior wire offers upward push to the higher subscapular nerve, thoracodorsal nerve and decrease subscapular nerve. The medial wire offers upward thrust to the medial pectoral nerve, medial cutaneous nerve of the arm and medial cutaneous nerve of the forearm.

The posterior cord is part of the brachial plexus. It includes contributions from all the roots of the brachial plexus. Posterior twine. Plan of brachial plexus.

Learn more about nerve cord here:-brainly.com/question/26348097

#SPJ4

3 0
1 year ago
What are some erosive forces?​
quester [9]

Answer:

Erosive Forces:

•light particles float

• some particles dissolve into water

• abrasive forces wear down rocks

3 0
3 years ago
Read 2 more answers
What is the most common pulse given by bats?
MakcuM [25]

Explanation:

Echolocation is one of the methods of orientation mainly used by the microchiropteran or insectivorous bats. While flying, these bats emit high frequency ultrasound. These sound pulses hit obstacles like rocks, trees, walls etc. and their echoes are heard by bats.

4 0
2 years ago
What is the primary mechanism associated with the role of fluoride in prevention of dental caries?​ a. ​Fluoride increases calci
MAXImum [283]

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.

7 0
2 years ago
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