Answer:
The proton–proton chain, also commonly referred to as the p–p chain, is one of two known sets of nuclear fusion reactions by which stars convert hydrogen to helium.
Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. Hope I’ve helped ;)
The answer is; B is younger than D
In sedimentary rocks, the bottom layers are older that overlaying layers. This is because sediments are placed on top of each other by surface runoffs to ocean beds. Therefore, the first sediments to be deposited will always be towards the bottom as more and newer ones are brought in and deposited.
<h2>Down Syndrome</h2>
Explanation:
Down syndrome is a genetic disorder caused when abnormal cell division results in an extra full or partial copy of chromosome 21
- Down syndrome is a genetic disorder caused when abnormal cell division results in an extra full or partial copy of chromosome 21
- Down syndrome is usually caused by an error in cell division called nondisjunction which results in an embryo with three copies of chromosome 21 instead of the usual two
- Prior to or at conception, a pair of 21st chromosomes in either the sperm or the egg fails to separates
- With development in embryo the extra chromosome is replicated in every cell of the body;this type of Down syndrome which accounts for 95% of cases is called trisomy 21
- Maternal age is the only factor that has been linked to an increased chance of having a baby with Down syndrome resulting from nondisjunction;here environmental agents such as drugs, chemicals, and radiation act as mutagens which induce mutation in the fetus
