With the severe changes to natural environments, many species are coming into contact with other species from which they were on
ce separated, and sometimes members of the different species mate and produce hybrid offspring. One example of this is the pizzly bear, a cross between a polar bear and a grizzly bear. One concern from such hybridizations is that the hybrids tend to not survive long enough to reach reproductive age, many not even completing development. What isolating mechanism is being described here?
Reproductive isolation can occur due to prezygotic or postzygotic isolating mechanism. Prezygotic mechanism prevents fertilization of gametes and can occur due to different mating behavior, different mating time period etc. Postzygotic mechanism occurs after the formation of zygote i.e. the organisms are able to mate and fertilization also occurs. However the resultant zygote may not survive. It might not survive immediately or might die before reaching the reproductive maturity. Such a situation would still come under reproductive isolation because the resultant offspring is not viable and not able to pass on the genes to the next generation.
B. có nhiều hệ sinh thái khác nhau trên trái đất. mỗi hệ sinh thái có một đặc tính riêng và chúng có thể kết nối, tác động qua lại với các hệ sinh thái khác
The nitrogenous bases Adenine form two hydrogen bonds with thymine and the cytosine form three hydrogen bonds with the guanine. Simply, A combines with T and G combines with the C. It is often called as a complementary base pairing because of each base pair bonds only with its specific complementary base partner in a DNA molecule.
Answer is: when the carbon atoms of the glucose molecule are broken apart in glycolysis and the Krebs cycle, result is a. CO2 and ATP.
In Krebs cycle aerobic organisms release stored energy through the oxidation of acetyl-CoA derived from glucose into carbon dioxide and chemical energy in the form of adenosine triphosphate (ATP).
