Alex, his mother, his father, and his older sister have blood type B. His younger sister and his brothers have type O. Anna, her mother, her father, and her younger brother have type A. Her sister and her older brother have type O. If Alex and Anna have three children, what is the probability at least two of them will have type O

25%

Explanation:

the probability at least two of them will have type O can be solved as follows

Let the chances be

(Chance of Alex is I^B I ) x (1-none have type O) X (Chance of Anna is I^A i)

=>>(2/3) x (1-.75 3 ) x (2/3)= 0.25

So 0.25x 100 = 25%

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.