Answer:
Environmental awareness is an incredibly important part of our lives. In order to protect the sustainability of the planet, everyone needs to commit to becoming more environmentally aware. Environmental degradation is detrimental and is jeopardising the long-term health and security of animals, plants and humans.
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Answer:
When you sit on a plane for 6 hours without moving, blood accumulates in your veins, and the moment you get up, gravitational forces affect venous return, cardiac output, blood pressure, and venous pressure. That way, when you're sitting on a plane, the gravitational force is the same at the upper and lower extremities, such as the chest, abdomen, and legs, causing venous blood pressure and volume to be evenly distributed throughout the body. However, when one gets up, one becomes dizzy because of abnormal regulation of blood pressure. This is because gravity causes blood to accumulate in the lower extremities (veins of the legs and trunk). This lowers the blood pressure and the blood that the heart pumps. By causing blood to accumulate in the lower extremities, and as venous compliance increases, the veins expand with blood that causes the volume of blood to shift in the veins. This increases the volume and venous pressure in the lower extremities when standing. And the volume of thoracic venous blood is less and less central venous pressure. This leads to a decline in stroke volume. Cardiac output and mean arterial pressure also decrease as left ventricular stroke volume decreases, reducing pulmonary venous return. Decreased standing blood pressure, referred to as orthostatic or postural hypotension. Thus, lowering blood pressure decreases cerebral blood flow, which means less range of blood in the brain causing dizziness.
Explanation:
Answer:
E2F transcription factors
Explanation:
The E2F transcription factors (TFs) encode intracellular factors associated with the control of the cell cycle. E2F are TFs that bind to promoter consensus sequences in order to activate transcription. These TFs control the expression of target genes involved in cell proliferation including, among others, genes for DNA replication and mitotic activation. Moreover, the E2F proteins also may act as a link between cell fate and the cell cycle. The retinoblastoma (Rb) is a protein that modulates the activity of the E2F family of TFs, and it has been shown that the Rb/E2F pathway is a key molecular mechanism associated with cell proliferation.
Answer:
The fact that most eukaryotes reproduce sexually is evidence of its evolutionary success. In many animals, it is actually the only mode of reproduction. The genetic diversity of sexually-produced offspring is thought to give species a better chance of surviving in an unpredictable or changing environment.
