The Count of Things

Bluebulb Projects' The Measure of Things presents:

It's about the number of Teeth in a Great White Shark's Mouth.

(Carcharodon carcharias) (average; including developing rows)
A Great White Shark has 48 exposed teeth on their upper and lower jaws. Behind these exposed teeth are developing teeth — up to 300 in about 5 rows. The sharks will continuously lose and replace the exposed teeth throughout their lives.

It's about nine-tenths the number of Countries in Africa.

In other words, 48 is 0.89 times the count of Countries in Africa, and the count of Countries in Africa is 1.1 times that amount.

(2016 figures) (sovereign states recognized by the UN only)
The continent of Africa includes 54 sovereign countries recognized by the United Nations as of 2016. It is the second-most populous continent in the world, with 1.1 billion inhabitants.

It's about two-thirds the number of Submarines in the US Navy.

In other words, the count of Submarines in the US Navy is 1.5 times 48.

(a.k.a. Subs) (includes all types, all classes) (2015 figures)
The United States Navy maintains a fleet of 72 active submarines. A typical submarine goes to sea with a crew of about 140.

It's about one-and-seven-tenths times the number of Countries in the European Union.

In other words, the count of Countries in the European Union is 0.59 times 48.

(a.k.a. EU) (2016 figures)
There are 28 member countries in the European Union, the latest member of which is Croatia. The EU is largely urban, with sixteen cities having a population of one million or more, and 75% of the population living in an urban area.

It's about half the number of Keys on a Piano.

In other words, 48 is 0.55 times the count of Keys on a Piano, and the count of Keys on a Piano is 1.8 times that amount.

(Moden layout; A₀ to C₇)
Most modern keyboards have 88 keys, comprising seven octaves and an additional major third. A full-size, acoustic piano may have as many as 12,000 separate parts.

It's about half the number of Wolves in Yellowstone National Park.

In other words, 48 is 0.462 times the count of Wolves in Yellowstone National Park, and the count of Wolves in Yellowstone National Park is 2.16 times that amount.

(a.k.a. Henihco'oo; a.k.a. Héetíhco'oo) (December 2014 figures; Wyoming Park area)
As of the 2014 population count, there were 104 wolves living in Yellowstone National Park, in twelve packs. All of the wolves now living in the Park are thought to have descended from the 66 wolves (re)introduced into the Park in 1995-96.

It's about two-fifths the number of Elements on the Periodic Table.

In other words, 48 is 0.407 times the count of Elements on the Periodic Table, and the count of Elements on the Periodic Table is 2.46 times that amount.

(a.k.a. Periodic Table of the Elements, a.k.a chemical elements) (confirmed elements as of 2016)
From element number one, hydrogen, to element one-hundred eighteen, ununoctium, there are 118 confirmed elements on the Periodic Table. Ninety-four of the elements exist in nature, and the remaining twenty-four have only been synthesized in labs (not having occurred naturally in the time since scientists have begun researching them)