Stars are formed in clouds of dust and gas (nebulae.) Nuclear reactions at the center (core) of stars gives enough energy to make them shine brightly for many, many years. The exact l<span>ifetime of a star depends on its size.</span>
Edwin Hubble used the Doppler effect to determine that the universe is expanding. After years of scientific research and observation of different celestial bodies through a telescope, Hubble found that the light from distant galaxies was shifted towards the red end of the spectrum. This red shift indicates that stars are moving away from us and from each other. This phenomenon is called the 'expansion of the universe', also known as the big band theory.
1.14 astronomical units.
Please leave me a "brainliest" and thanks to help me out, if I helped you!
<span>The stage at which all the cells show crossover chromosomes is meiotic prophase I. The crossover is the exchange of genetic material between homologous chromosomes. Homologous chromosomes are present in the meiosis I. Regarding the phase of meiosis I, it is expected that the crossover takes place in meiotic prophase I since homologous chromosomes pair up in the prophase.</span>
