Answer:
Villi
Explanation:
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Answer:
B) oaks and other sexually reproducing, extant (currently living) trees
Explanation:
The biological species concept defines the species on the basis of their reproductive isolation. It states that when individuals are able to interbreed to produce fertile and viable progeny, they belong to the same species. The members of different biological species cannot interbreed. If they interbreed, either pre-zygotic or post-zygotic isolation mechanisms do not allow the production of fertile progeny.
Therefore, the biological species concept can be applied to the organisms that are able to reproduce sexually. The asexually reproducing organisms would not exhibit any reproductive isolation which is a key criterion to group organisms under different species. Among the given examples, biological species concept can be applied to the sexually reproducing extant trees such as oak.
Since we cannot deduce the reproductive isolation in sexually reproducing extinct species, the concept is not useful for dinosaurs which are extinct now.
Meninges refers to the three layes of membranes surrounding the brain and spinal cord of the mammals. The inflammation of these protective membranes of the brain and the spinal cord caused by the infection of bacteria, virus or other microorganisms is called the meningitis.
A laboratory test to identify or rule out meningitis is the analysis if the cerebrospinal fluid (CSF) by lumbar puncture. CSF is a colorless fluid filling the ventricles of the brain and the central canal of the spinal cord. Lumbar puncture is a techinque of isolating the CSF from the sac sround the spinal cord using a needle under a local anesthetic. The sample is then analysed for the opening pressure which is normally between 6 and 18 cm of water in a patient who is not infected with meningitis. Also, the levels of glucose in CSF is above 40% of that in blood in non-infected persons. If lactate levels are less than 35mg/dl, this will also rule out meningitis.
Answer:
aortic arches (earthworms)
Explanation:
Earthworms vessels link together
