Smoking reduces a person's life span by an average of
a.
the number of tobacco users has increased.
b.
the number of tobacco users has decreased.
c.
the number of tobacco users has not changed.
d.
the number of adolescent tobacco users decreased, while the number of adult users increased

The model illustrates a process by which a substance is taken up by a cell

Flock x flock y flock z total pieces of food eaten (from previous page) 147 93 60 food percentage* % % % simulated number of birds in flock for 3rd generation** * divide each flock's total pieces of food by 300, the total number of pieces of food eaten. ** multiply the food percentage for each flock by the total number of birds (30).

Depending on the organism the number of in a cell may change