In normal humans, sex cells contain the number of chromosomes

46.

Explanation:

Humans are diploid organisms, in which both somatic and sex cells have 23 pairs of chromosomes or 46 chromosomes. However, types of chromosomes are different in sex cells of males and females.

In males, there are 22 pairs of autosomes and the 23rd pair contains one X and one Y chromosome ( represented as 44 + XY), while in females, there are 22 pairs of autosomes and 23rd pair consists of two X chromosomes (represented as 44 + XX).

Thus, the correct answer to be filled in the blank is '46.'

straight or amphibians are homeothermic to thermal

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.