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Katarina [22]
2 years ago
13

In 1967 a penicillin-resistant pneumonia, caused by Streptococcus pneumoniae and called pneumococcus, surfaced in a remote villa

ge in Papua, New Guinea.
At about the same time American military personnel in southeast Asia were acquiring penicillin-resistant gonorrhea from prostitutes. By 1976, when the soldiers had come home, they brought the new strain of gonorrhea with them and physicians had to find new drugs to treat it.

In 1983 a hospital-acquired intestinal infection caused by the bacterium Enterococcus faecium joined the list of bacteria that could not be killed by penicillin.
Which of these BEST describes why certain bacteria have become resistant to penicillin?
A) The penicillin in the 1970's was much weaker that the penicillin used today, thus it was not as effective.
B) Penicillin was not effective in treating any bacterial diseases, so the doctors had to find new treatments.
C) These new bacterial strains came out of the jungles and forests already equipped to be penicillin-resistant.
D) Penicillin was so heavily prescribed by doctors that it led to certain, more fit, strains of bacteria to be able to survive.
2)
Biology
2 answers:
ser-zykov [4K]2 years ago
5 0

I think B but i’m not for sure

dedylja [7]2 years ago
5 0

Answer:

D. Penicillin was so heavily prescribed by doctors that it led to certain, more fit, strains of bacteria to be able to survive.

Explanation:

Researchers thought penicillin was the cure for all, and thus it became overused. Through natural selection, new, stronger strains of bacteria developed.

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Flatworms use a system of canals and tubes with the ______ as their excretory organ.
Kazeer [188]
<span>Flatworms use a system of canals and tubes with the mouth as their excretory organ. They belong to the Phylum Platyheminthes. </span><span>Flatworms can be cut in half creating two individuals by binary fission. Binary fission is a type of asexual reproduction in which the offspring has the same features and characteristics of the parent. During binary fission, the DNA replicates into two and goes at the end of each membrane. And then the cell membrane divides into two daughter cells. Then cytokinesis follow.</span>
6 0
2 years ago
Describe the structure of a neuron. Include the cell body, dendrites, and axon in your description. How does the structure of a
igomit [66]

Answer: A neuron has three main parts: dendrites, an axon, and a cell body or soma , which can be represented as the branches, roots and trunk of a tree, respectively. A dendrite (tree branch) is where a neuron receives input from other cells. Dendrites branch as they move towards their tips, just like tree branches do, and they even have leaf-like structures on them called spines.

The axon (tree roots) is the output structure of the neuron; when a neuron wants to talk to another neuron, it sends an electrical message called an action potential throughout the entire axon.

The features of neurons help them to carry out their function efficiently:

they have a long fibre (axon) so they can carry messages up and down the body over long distances

in a stimulated neuron, an electrical nerve impulse passes along the axon

the axon is insulated by a fatty (myelin) sheath - the fatty sheath increases the speed of the nerve impulses along the neuron

at each end of the neuron are tiny branches (dendrons), which branch even further into dendrites - the dendrites receive incoming nerve impulses from other neurons

Explanation:

Hope this is helpful!!

4 0
2 years ago
How does filtration occur during the formation of urine?
victus00 [196]
<h3><u>Answer</u>;</h3>

A. Pressure causes water and dissolved substances to filter through capillary walls of the glomerulus.

<h3><u>Explanation;</u></h3>
  • <em><u>During filtration the flow of blood in the glomerulus creates hydrostatic pressure in the glomerulus which forces molecules through the glomerular filtration membrane. </u></em>
  • Normal filtrate contains of water, glucose, amino acids, urea, creatinine, and solutes such as sodium chloride, calcium, potassium and bicarbonate ions.
3 0
2 years ago
Read 2 more answers
Control of respiratory processes is similar to control of cardiovascular in that . . . a. norepinephrine on alpha receptors caus
erica [24]

Answer:

b. epinephrine on beta 2 receptors causes bronchodilation

Explanation:

This is because epinephrine is an hormone and neurotransmitter that stimulate beta 2 receptors which causes signaling and their in presence in airway smooth muscle causes bronchodilation, which counter the activation of the M3 muscarinic receptors in cardiovascular. When stimulate in skeletal muscles it can lead to increased contractility and also to muscle tremors.

3 0
2 years ago
Two students are working together to Gram stain a mix of Gram positive and Gram negative cells. One of the students accidentally
Rasek [7]

Answer:

C.Both Gram positive and Gram negative cells would appear purple.

Explanation:

Gram staining is a technique used to differentiate bacteria to two main groups based on their difference in cell wall components.

Crystal violet, decolorizer(ethanol) and a counter stain are used.

Gram positive bacteria have a thicker peptidoglycan layer hence they will retain the crystal Violet stain even after decolorization. They will stain purple

Gram negative will stain pink due to losing the initial stain and taking up the counter stain after decolorization.

Therefore, if water is used instead of ethanol. Both bacteria will retain crystal violet stain in their cell wall.

6 0
3 years ago
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