How many chromosomes decide the sex of a platypus?

Why are the elements in the same vertical column called families? Is that any contribution made by marxist theory? What type of sonar is the most effective in detecting relatively close contacts and formulating a firing solution? How do you express density as a decimal? What is 9 stone in kilograms? How should a human be called according to the binomial system? If you left South America and sailed East along the equator what continent would you end up at? Why do rocks have cracks? What will the voltage drop on a 1.5 mm cable run 1.5 kilometres be? Does blue colour release calming hormones to the brain? Why water is important to cells Water? Where did Jane Goodall go for elementry school? Who discovered binoculars? What is the intermolecular force of k2cro4? What is stimulus threshold? What are some reasons why plants would be in a clumped spatial pattern? Is distilled water good for dogs? Are Rose petals poisonous to children? Is cellular respiration part of the carbon cycle? What type of blood vessel carries carbon dioxide away from the cell?