Class interval should always be a whole number and yet in this case we have a decimal number. The solution to this problem is to round off to the nearest whole number. In this example, 2.8 gets rounded up to 3. So now our class width will be 3; meaning that we group the above data into groups of 3 as in the table below.
Skeletons come in a number of forms, each suited for a particular set of lifestyles and environments. Skeletons can be rigid, semirigid, or soft. They can also be external or internal. Vertebrates have internal skeletons, called bony skeletons, which consist mainly of calcified bone tissue. Most invertebrates, such as insects, spiders, and crustaceans, have outer skeletons called exoskeletons.
While vertebrates all have skeletons to give their bodies shape and support, invertebrates have no bones. Many of the invertebrates have an exoskeleton, or a hard outer shell, as their skin to act like bones do.hen some people think of skeletons, they think of Halloween or some mad scientist's display in a laboratory. But we all have a skeleton. It is what gives our bodies shape and form. Without a skeleton, we would be a heap of skin and muscles.