One type of density change is mass over volume.
The abdominal cavity is the answer you are looking for.
In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46.
Tomatoes are commonly grown from seedlings started indoors that are later transplanted into the garden. Tomato seeds are commonly planted indoors as early as 8 to 6 weeks before the average date of the last spring frost. Tomato seedlings are usually transplanted into the garden 1 to 3 weeks after the last frost. Wash tomatoes under cool running water.
Slice an "X" on the bottom of each tomato with a small utility knife. In a large saucepan bring water to a rolling boil. Fill a large mixing bowl with ice cold water. With a large spoon, place tomatoes in boiling water for 30 seconds to loosen skin. Remove tomatoes after 30 seconds, place directly into cold water to stop the cooking process. Core the tomatoes by removing the stem with a paring knife. Peel away the skin, being careful not to injure the flesh of the tomatoes.
That's because it helps migrate the serves in 2 important purposes: conserve (save) energy and it is easy to keep track for the birds to fly in the group.
:) :) :)