Answer:
Carbon based rings & chains form very large molecules because carbon can form up to 4 covalent bonds to form these rings and chains, and these bond with other rings and chains over and over. ... Lipids, proteins, carbohydrates, and nucleic acids are the 4 main types of carbon-based molecules in organisms.
Explanation:
Answer:
Option (3).
Explanation:
Teratogens may be defined as the chemicals that can cause birth defects in the fetus. Substances like alcohol, lead and nicotine acts as the main agents of tertaogens.
Shamona is drinking water that contains high level of lead. The element lead is harmful for the fetus. Even the small concentration of lead is enough to cause birth defects. The lead exposure can cause the abnormal development of brain and damages the brain of fetus. The fetus has low birth weight also.
Thus, the correct answer is option (3).
The identification of an individual by the means of genetic engineering is possible because the Y chromosomes in the males does not experience any crossing-over as there is only a single Y chromosome present in a human male.
The mitochondrial DNA is passed from the mother to child in the cytoplasm of the cell, and it is passed on without any changes. The X chromosome is can be passed from a mother to her son as he will receive Y chromosome from his father.
Hence, the correct answer is 'Option B - The Y chromosome does not experience crossing over'.
