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.
The boundary between conducting zone and respiratory zone structures occurs at the terminal bronchiole/respiratory bronchiole junction. The major respiratory structures span the nasal cavity to the diaphragm. Functionally, the respiratory system can be divided into a conducting zone and a respiratory zone. The conducting zone of the respiratory system includes the organs and structures not directly involved in gas exchange. The gas exchange occurs in the respiratory zone.
The meaning is, "the taking in of matter by a living cell by invagination of its membrane to form a vacuole."
Answer:
Hormones are molecules produced by the endocrine system that send messages to various parts of the body. They help regulate your body's processes, like hunger, blood pressure, and sexual desire. While hormones are essential to reproduction, they are fundamental to all the systems of your body.
