The vertebral column, when seen from the side, has 4 curves: 2 convex curves (cervical and lumbar curves) and 2 concave (thoracic and sacral curves). This curves are the feature of the skeleton that allow a child to maintain balance in the upright position eventually.
When we are born we have a single concave curve throughout the whole vertebral column but, as we grow, still in the early months as we try to hold our head, the cervical curve starts to develop, and later, as we try to sit up, stand up, and walk, the lumbar curve aslo starts to develop. In few years we have all curves fully developed.
<span>The correct answer is A. sometimes your perception of the problem shifts as you seek to solve it. The more you think about a problem, the more likely are you to change your opinions about it, and your approach to solving it. You may also realize that the problem is not as serious as you originally thought it was, so take your time to think about it.</span>
Most organisms can tolerate a very narrow pH range close to neutral, i.e., around pH 7. It is likely that there would not be much life in the lake at pH 3. Once the pH increases to above 5.5 to 6, it is more likely that life would begin to survive. Once the pH rises to above around 9, the solution is starting to become basic, and once again, few organisms will survive.
The half- life of carbon is 5600 years.
Answer: 25% of the heterozygous cross are short, and the offspring of a homozygous dominant and homozygous recessive pea plant will always display the dominant trait (phenotype), because they are heterozygous.
Explanation:
In this explanation, I'm assuming that the allele "T" for tall plants is dominant to the allele "t" for short plants, like in Gregor Mendel's pea plant experiment.
A homozygous tall pea plant will have the genotype "TT" and a homozygous short plant will have the genotype "tt" because homozygous means that both alleles are identical. Since "T" is dominant over "t", any plant with at least one "T" allele will be tall (the dominant trait), regardless of what the other allele is. Let's look at a Punnett square for this cross:
Each of the offspring has one "T" allele, so they are all tall plants. This is because the "T" allele is dominant over the "t" allele, so a plant with one "t" allele and one "T" allele will only display the traits of the "T" allele, which in this case is a tall pea plant.
If we cross the offspring, we get a Punnett square that looks like this:
The "TT" and "Tt" crosses both have at least one "T" allele, so they are tall plants. However, the last cross "tt" doesn't have any "T" alleles and is short, because it is homozygous recessive . Since 1 out of 4 pea plants are short, or 1/4, the probability of a short pea plant from a heterozygous cross is 25%.