Answer:
The correct option is d) head.
Explanation:
Bicoid protein works as a transcription factor. It enters the nuclei of the embryos in early segmentation, where it activates the hunchback gene. In Drosophila, embryonic development begins at the time of fertilization. The sperm enters the mature oocyte through the micropile, a structure located in what will be the anterior region of the egg. Bicoid and hunchback mRNAs, protein products are critical for the formation of the head and thorax. Already in the early stages of oocyte development, certain mRNAs are located in specific regions of the oocyte: mRNA molecules encoding the Bicoid protein are preferentially located in the anterior region of the oocyte. Moderate levels of the bicoid protein are necessary to activate the formation of the thorax (i.e., the expression of the hunchback gene) but the formation of the head requires high concentrations of Bicoid, the promoters of a specific gap gene of the head must have sites of low affinity binding for Bicoid, so that this gene can be activated only in extremely high concentrations of Bicoid.
The lack of Bicoid protein affects the formation of the head and other structures in the anterior region of the oocyte.
Answer:
The effects of weathering disintegrate and alter mineral and rocks near or at the earth's surface. This shapes the earth's surface through such processes as wind and rain erosion or cracks caused by freezing and thawing. Each process has a distinct effect on rocks and minerals.
<span>Punctuated
Equilibrium/ Equilibria proposes that once species appear in the fossil record,
the population will be in the state of
little or absent morphologic change. This is called a state of stasis. The
theory further proposes that the population is confined to infrequent and
geographical rapid events when significant evolutionary change happens. The parent species will the split into two
distinct species. This process if called cladogenesis.</span>
)Sexual reproduction maintains a constant level of variation in the population and requires less energy.
