Which of the following is considered to be the only natural permanently magnetized material?
alnico
lodestone
magnetite
iron

The correct answer is "lodestone".

Explanation:

Lodestone is a naturally occurring magnet comprised of a magnetized form of magnetite. Its name come from the term "leading stone" because it was first used for navigation purposes to create magnetized iron that was used as a magnetic compass. Lodestone is permanently magnetized and is the strongest magnet found in nature.

the diploid number of chromosomes is sometimes represented by the symbol 2n. for the fruit fly, the diploid number is 8, which can be written as 2n = 8, where n represents twice the number of chromosomes in a sperm or egg cell.