The structure of DNA is called a double helix because DNA is made up of two strands of nucleotides wound together in a spiral.
DNA has two strands that run opposite of each other and twist together much like a twisted ladder. Each backbone of the ladder is made up of alternating groups of sugar and phosphate groups.
Answer:
The correct answer is option c. "Tetracycline must be discontinued before beginning the isotretinoin".
Explanation:
Isotretinoin is a medication used to treat cases of severe acne, having dramatic positive effects since the patients start the treatment. However, the use isotretinoin should be monitored by a doctor because it is hard to process and could cause renal side effects. In this case, the patient must discontinue its treatment with tetracycline before start using isotretinoin.
Answer:
temporal reproductive isolation
Explanation:
The correct answer would be temporal reproductive isolation.
<u>Reproductive isolation</u> generally refers to series of biological mechanisms or processes that prevent members of different species from mating/fertilization or prevent the product of their mating to be invalid.
Some reproductive isolation processes prevent members of different species from mating or prevent fertilization as a result of mating. These processes are known as pre-zygotic reproductive isolation mechanisms.
Some other processes ensure that the product of fertilization (when it occurs) is invalid. These are known as post-zygotic isolation mechanisms.
<em>A good example of the pre-zygotic reproductive isolation process is </em><em>when closely related by different species bloom at different times</em><em>. This will prevent mating or cross-pollination to happen between the different species. This is known as temporal reproductive isolation.</em>
Answer:
The nervous system has two main parts:
The central nervous system is made up of the brain and spinal cord.
The peripheral nervous system is made up of nerves that branch off from the spinal cord and extend to all parts of the body.
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Answer:
Stars are classified by their spectra (the elements that they absorb) and their temperature. There are seven main types of stars. In order of decreasing temperature, O, B, A, F, G, K, and M.
Explanation:
O and B stars are uncommon but very bright. M stars are more common but dim.
