Answer:
According to Darwin's theory of evolution, new species evolved as a result of natural selection.
Explanation:
- Darwin proposed that speciation could readily occur through the prolonged action of Natural selection.
- Natural selection allows the 'survival of the fittest' i.e. a more fit organism will have a better chance of survival than the less fit one.
- The result of Natural selection could be positive,negative or balancing.
- Evolutionary process in which the genetic changes confer a higher fitness to increase frequency of the organism over time in population is called positive selection.
- Evolutionary process in which genetic changes decreases the organism's fitness resulting in its disappearance from the population is called Negative selection.
- It may happen that a mutation benefits hetero-zygotes but not homo-zygotes and alleles maintain a intermediate frequency in population.This evolutionary process is called balancing selection.
<span>A: The proportions of a population that are at different age levels make up the population’s age structure. </span>
Answer:
The correct answer is ''All of the choices are correct.''
Explanation:
Pregnant women are a risk group for listeriosis, the disease caused by the Listeria monocytogenes bacteria found in contaminated food. This organism can cross the placenta and affect the fetus. Due to the decrease in cellular immunity, pregnant women are part of the population at risk and are 17-20 times more likely to develop listeriosis after the consumption of contaminated food and it usually occurs from the third trimester and appears as a disease mild with not very high fever, joint and muscle pain. Listeriosis can cause miscarriages during the first three months of pregnancy. As the third trimester is reached, the mother is at greater risk. It presents a 40-50% fetal or neonatal mortality. In the first or second trimester it produces septic abortions and intrauterine fetal death, in the third trimester she produces chorioamnionitis and premature labor. In 1/3 cases it can occur asymptomatically in the fetus / neonate. In newborns, listeriosis can cause blood infections and meningitis.
Answer:
DNA template sequence:
5' TGACCAAGT 3'
RNA antisense sequence: 3' UGACCAAGU 5'
>>> RNA sense sequence (transcript) : UGAACCAGU
Explanation:
In the DNA molecule, four types of nitrogenous bases are found: cytosine (C), and guanine (G), adenine (A) and thymine (T). In DNA the bases pair up with each other in the following ways: A pairs with T by two hydrogen bonds, while C pairs with G by three hydrogen bonds. In RNA (i.e., transcript sequence), T is replaced by uracil (U). Moreover, the RNA nucleotide sequence is read in the direction 5' to 3'.
