7) A) secondary oocyte; vesicular follicle B) secondary oocyte; secondary follicle C) ovum(egg); vesicular follicle D) primary oocyte; secondary follicle Answer: A 8) Development of the oocyte and follicular growth occur in the ________ of the ovary. 8) This is the end of the preview.
Evolution of the atmosphere. Scientists believe that the Earth was formed about 4.5 billion years ago. Its early atmosphere was probably formed from the gases given out by volcanoes. It is believed that there was intense volcanic activity for the first billion years of the Earth's existence.The early atmosphere was probably mostly carbon dioxide, with little or no oxygen.There were small quantities of water vapour, ammonia and methane. As the Earth cooled down, most of the water vapour condensed and formed the oceans.ts early atmosphere was probably formed from the gases given out by volcanoes. It is believed that there was intense volcanic activity for the first billion years of the Earth's existence. The early atmosphere was probably mostly carbon dioxide, with little or no oxygen.
The age of Earth is approximately one-third of the age of the universe. An immense amount of geological change has occurred in that timespan, accompanied by biological change. Earth formed around 4.54 billion years ago by accretion from the solar nebula. Volcanic outgassing probably created the primordial atmosphere and then the ocean; but the atmosphere contained almost no oxygen and so would have been toxic to most modern life including humans.