A.) Rearrange and form new substances with new properties
Explanation:
According to Dalton's atomic theory, atoms are the smallest parts of elements. In chemical reactions atoms will re-arrange and form new substances with new properties.
- The holy grail of the Dalton's atomic theory is the indestructible nature of atoms.
- Atoms were considered to be the smallest and the thinnest particles of any substances.
- In chemical reactions, atoms only recombine.
- Atoms are not broken down into any simpler substances.
- Atoms cannot be created nor are they destroyed. They only recombine to form new compounds.
- They cannot be turned completely to energy according to Dalton's theory. But nuclear reactions nowadays refutes that.
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Answer:
A scientist’s presentation of experimental results at a scientific conference
Explanation:
The correct answer is d: cDNA.
<span>cDNA or complementary DNA is DNA synthesized usually from messenger RNA (mRNA) by the enzyme reverse transcriptase. Because this molecule is from mRNA it contains only exons. cDNA is also produced naturally by retroviruses, for example, HIV virus.</span>
Answer:
Some diseases are more common in certain groups of people, such as Caucasians or African Americans because individuals in such ethnic groups often share certain alleles (versions of their genes), that have been passed down to them from common ancestors and a particular genetic disorder may be more frequently seen in such groups if one of these shared genes contains a disease-causing mutation.
Explanation:
Some genetic diseases are frequently seen in certain ethnic groups like Caucasians or African Americans. Individuals in such groups often share certain alleles (versions of their genes), that have been passed down to them from common ancestors and one of these shared genes may contains a disease-causing mutation.
Examples of certain genetic disorders that are more common in particular ethnic groups include the Tay-Sachs disease, which is more common in people of eastern and central Europe (Ashkenazi), Jewish or French Canadian ancestry and the sickle cell disease, which occur among people of African, African American, or Mediterranean heritage.
Some genetic disorders are more common in people whose ancestry can be traced to a particular geographic area. The factors that can lead to development of populations with very different genetic allele frequencies include their geographic origin, selection, patterns of migration, historic events, etc. Certain natural barriers like oceans and other water bodies, high mountains, large deserts, or major cultural factors had prevented communication and interaction between people. So mating was restricted within the group, and this produces genetic marker differences and differences in the presence of specific disease-related alleles.
