Answer:
Amniocentesis is an invasive method that involves the aspiration of 10-20 ml of fetal water through the abdominal wall under ultrasound-guided control. In most cases, the procedure is performed around the 16th week of gestation. The fetal water sample contains fetal cells, mostly cells of fetal skin and the epithelium of the urinary tract.
Chorionic Villus Sampling (CVS) biopsy is performed between weeks 11 and 12 of gestation. During biopsy, with ultrasound guidance, the tissue of the chorionic fossa is aspirated mainly across the abdomen (transabdominal pathway). The biopsy specimen is of fetal origin and belongs to the outer layer of blastocyst cells or the trophoblast (outer layer of the placenta). Very often, the biopsy specimen contains tissue of the decidua (mucous membrane of the uterus) that is of maternal origin, and it is necessary to remove the maternal tissue before any treatment of the sample.
Explanation:
The amniocentesis procedure carries a risk of miscarriage of 0.5-1%. After aspiration of the fruit of the water, the sample is centrifuged to separate the cells from the amniotic fluid. Separate cells are seeded on a nutrient medium (cell culture) that stimulates cell growth. After about 14 days, the cell culture is further used for various genetic or biochemical analyzes such as karyotyping.
The advantage of chorionic biopsy is the amount of biological material, which is sufficient for the whole a number of different laboratory procedures. Also, a great advantage is the timing of the procedure as it allows diagnosis in the first trimester of pregnancy, but the chorionic biopsy procedure itself carries a risk of miscarriage of 1-2%.
The indispensable chemical element is carbon.
The correct answer is D. House cats, lions, and tigers belong to the same class and family.
Explanation:
Taxonomy classifies animals using different levels such as kingdom, family, order, species, etc. that show the features of the organism and its relationship or similarities with others. In the chart presented, the only level that is different for the three animals is the last one, which is the species level because in this the cat is classified as Domesticus, the lion as Leo, and the tiger as Tigris. This implies the other levels including the class (Mammalia or mammal) or family (Felidae) is the name of the three animals. This makes the last answer correct and shows these three animals are closely related.
<span>The answer is D. pairs uracil with adenosine instead of thymine. Through the process of elimination, both DNA and RNA contain nitrogenous bases. However, DNA contains sugar deoxyribose within its nucleotide components while RNA contains sugar ribose. Also, DNA has 2 strands wrapped in a helix while RNA has only 1 strand. Thus, the correct choice is D. because RNA pairs uracil with adenosine instead of thymine like DNA.</span>
