A: On 12 September 2001, less than 24 hours after the terrorist attacks against the United States, NATO declared the attacks to be an attack against all NATO member countries within the terms of Article 5 of the North Atlantic Treaty.
Humans have an additional pair of sex chromosomes for a total of 46 chromosomes. The sex chromosomes are referred to as X and Y, and their combination determines a personâs sex. Human females have two XX chromosomes while males possess an XY pairing.
1 In humans, females have 23 homomorphic pairs and males have 22 homomorphic pairs plus a heteromorphic pair. 2  During meiosis, females produce only one kind of gamete all having one X chromosome. 3  Males produce two kinds of gametes, one with an X and the other with a Y chromosome. XX-XO system in which females have 2 X chromosomes. 2  Males have only 1 X and no additional sex chromosomes. 3  Females have an even number of chromosomes and males have an odd number of chromosomes. 4  This occurs in many species of insects.