They are based on their temperature and precipitation according to the <span>Köppen Climate Classification System</span>
Answer:
The main function of the RB protein is to inhibit the transition from the G1 to S phase. Its activity depends on its phosphorylation state: if RB is not phosphorylated (active state), it is bound to the transcription factor E2F, preventing its translocation to the nucleus and the activation of genes necessary for DNA synthesis; and if it is phosphorylated, by cyclin-CDK complexes, E2F is released and cell proliferation occurs.
Explanation:
Retinoblastoma (Rb) was the first tumor suppressor described and, as we know today, mutations in its structure determine a large number of cancers. Structurally, we speak of a large and multifunctional protein; which is organized in different domains. The activity of this protein is regulated, mainly, by phosphorylation at multiple sites described over the years and is involved in control mechanisms of the cell cycle, apoptosis and senescence.
I think the second option is the best (by making the ramps height and length equal) because the first option will require more pushing, the third option will only make the ramp lighter which could cause it to not stay in place, the last option would make it harder to push the boxes up because the rubber will make it harder to slide the boxes up. I hope this helps:)