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The answer is C. During one of his explorations, naturalist
Charles Darwin reached the Islands of the Galapagos. He observed that there are
the same species of animals on different islands, but have noticeable
differences. He found in Galapagos, that there were finches, a type of bird,
with different type of beaks. Birds used their beaks to acquire food. It led
him to discover that species developed over time to fit their way of life in
surviving and getting their food.
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Answer:
The correct answer is b. recognizes foreign DNA sequences that have previously entered the cell and directs the Cas proteins to destroy them.
Explanation:
Clustered regularly interspaced short palindromic repeats (CRISPER) is the sequences of DNA found in the genome of prokaryotes and archaea. These sequences are added at a crisper locus in DNA by bacteria through capturing bacteriophage DNA during infection.
Then this sequence is used to detect a similar sequence of bacteriophage during subsequent infection and destroy them by Cas9 enzyme. Cas 9 enzyme uses a crisper sequence as a template to destroy similar phage DNA.
So the CRISPER Cas system provides an adaptive defense mechanism to bacteria against foreign DNA coming from bacteriophage. Therefore the correct answer is b.
Answer:
The correct answer is D. Reduced levels of circulating estrogens.
Explanation:
Estrogens prevent the loss of calcium and ensure its proper mineralization, thus preventing the bones from becoming brittle, maintaining the consistency of the skeleton and preventing osteoporosis. Osteoporosis is a skeletal disease in which there is a decrease in bone mass density. Thus, the bones become more porous, the number and size of the cavities or cells that exist inside them increases, they are more fragile, they resist shocks worse and they break more easily. Menopause is the definitive cessation of ovarian function that, externally, results in the disappearance of the menses and usually occurs around 50 years (the interval goes from 45 to 55 years). It is the gradual loss of calcium in the bones, which accelerates in the first years of menopause due to estrogen deficiency. At the beginning of the disease, there are no symptoms and, as it progresses, there is a tendency to suffer fractures, which leads to a decrease in height.
One year. It takes 365 days for Earth to orbit the sun.
