Answer:
The principal difference in development of Dorsoventral axis in deuterostomes and protostomes is something called inversion
Explanation:
In protostomates the neural tube is below the gut and the dorsal vessel is above the gut while in deuterostomates is the oppossite, there is an inversion and now, the neural tube is above the gut and the heart tube is below. In both cases the development is related to the gradient of expression of some genes, where the expresion of one gene supress the formation of one structure in one side of the axis.
In protostomates the TGT-B factor is expressed dorsally and supress neural tube formation and ventrally a sog gene is expressed and supress TGT-F factor allowing neural tube to develop. In deuterostomates, an homolog of TGT-B family gene BMP-4 is expressed ventrally while dorsally BMP inhibitors (sog gene like) are expressed.
Accordingly to some researchers, the first state of the common ancestor of deuterostomates and protostomates had an protostomate-like orientation in dorsoventral axis
Answer: A warm front forms when a warm air mass pushes into a cooler air mass, also shown in the image. Warm fronts often bring stormy weather as the warm air mass at the surface rises above the cool air mass, making clouds and storms.
Answer:
The correct option is A. The cell is sitting in a hypertonic solution.
Explanation:
A hypertonic solution is a solution in which there are more number of solutes present in the solution than inside the cell. The solutes then tend to pass into the cell through diffusion from the solution.
As it can be seen in the diagram, the concentration of salt is more in the solution i.e 40%. Hence, the salt from the solution enters into the cell by diffusion and has a concentration of 10% inside the cell which shows the cell to be placed in a hypertonic environment.
Answer:
A solar eclipse occurs when the moon gets between Earth and the sun, and the moon casts a shadow over Earth. A solar eclipse can only take place at the phase of new moon, when the moon passes directly between the sun and Earth and its shadows fall upon Earth's surface
Explanation:
Answer:
A: Unlike DNA, XNA replicates conservatively
Explanation:
<em>The replication of the DNA is </em><em>semi conservative.</em><em> This means that newly replicated double helix DNAs usually consist of one parental strands and one newly synthesized strands. The parental DNA unwinds and each strand serves as template for the synthesis of complementary strands.</em>
In the case of XNA, the two strands of parental XNA were found intact, meaning that the newly produced XNA consist of two newly synthesized strands. This thus means that the replication process is conservative.
Hence, unlike DNA replication that is semi conservative, XNA replication is conservative.
