Your lab group is experimenting with the diffusion of molecules across a membrane. Dialysis tubing is used as a model cell membrane because is it semi-permeable, allowing small molecules to cross the membrane, but NOT larger molecules, like starch. A starch solution is placed in the dialysis tubing and then the dialysis tubing is placed in an iodine and water solution. Iodine is used as an indicator for the presence of starch. Normally, iodine is a yellow-brown color (on the left), but in the presence of starch, it turns a deep purple (right). After observing the experimental setup for 20 minutes, the iodine solution remains brown, but the starch solution inside the dialysis tubing is purple and swollen. What CANNOT be concluded from the results? A) Iodine is a small molecule and diffused through the dialysis tubing INTO the starch solution. B) Starch is a large molecule and could NOT diffuse through the dialysis tubing into the iodine solution. C) Starch requires ATP energy for transport and therefore cannot cross the dialysis tubing into the iodine solution. Eliminate D) The starch solution is hypertonic to the iodine solution, causing water to move across the dialysis tubing INTO the starch solution.

enzyme speed up the reactions

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.

answer-

the statement that f(x) = |x+a| + b has exactly one x-intercept is sometimes correct.

solution-

it solely depends on b, whether the function will have one or two or zero x intercept.

this plot of the given function, f(x) = |x+a| + b will be the basic absolute value graph i.e v shape, with vertex translated to (-a, b), instead of origin.

1-   if b is zero, the graph will have exactly one x-intercept, at x= -a

2- if b is positive, the whole graph will be above the x-axis, hence it will have no x-intercepts.

3- if b is negative, the graph will be below the x-axis, hence it will have two x-intercepts.

∴ the statement is sometimes true.