Hello!
So, day and night are caused because the earth makes a full rotation on its axis once every 24 hours.
That way, have of Earth is facing the sun (it is morning on that side) and the other half isn't (which is why it is nighttime over there).
For example, if it's nighttime in Canada and America, it's morning in Pakistan and India. This is because Pakistan and India are facing the sun whilst Canada and America are not.
A N S W E R:
The balls should be moved so that half the Earth is facing the sun and the other half is not. This would be 24 hours. As for the sun, it is a gas, not a solid, so it doesn't rotate like one. However, that does not mean that it is not rotating to some extent.
It makes sense that cell membranes are made of phospholipids because water cant mix in with lipids, so the phospholipids will be able to effectively block out any unwanted water or chemicals suspended in water outside of the cell.
Answer:
Purple colour arises due to the dominant alleles whereas white colour arises due to the recessive alleles.
For the purple colour to arise, even one of the dominant allele will be enough to cause the effect. On the other hand to see the recessive white trait, both the alleles of the gene should be recessive.
To ensure that only white flowers are grown, the farmers need to cross both white flowered plants to get the desired result.