Across was performed between a yeast strain that requires methionine and lysine for growth (met— lys—) and another yeast strain, which is met+ lys+. one hundred asci were dissected, and colonies were grown from the four spores in each ascus. cells from these colonies were tested for their ability to grow on petri plates containing either minimal medium (min), min + lysine (lys), min + methionine (met), or min + lys + met. the asci could be divided into two groups based on this analysis: group 1: in 89 asci, cells from two of the four spore colonies could grow on all four kinds of media, while the other two spore colonies could grow only on min + lys + met. group 2: in 11 asci, cells from one of the four spore colonies could grow on all four kinds of petri plates. cells from a second one of the four spore colonies could grow only on min + lys plates and on min + lys + met plates. cells from a third of the four spore colonies could only grow on min + met plates and on min + lys + met. cells from the remaining colony could only grow on min + lys + met. a. what are the genotypes of each of the spores within the two types of asci? b. are the lys and met genes linked? if so, what is the map distance between them? c. if you could extend this analysis to many more asci, you would eventually find some asci with a different pattern. for these asci, describe the phenotypes of the four spores. list these phenotypes as the ability of dissected spores to form colonies on the four kinds of petri plates.

Idont know but good luck; )

Environmental science studies the interactions between the physical, chemical, and biological components of the environment, including their effects on all types of organisms. earth science (also known as geoscience), is an inclusive term for all sciences related to earth (geology, meteorology, oceanogr maphy, etc).  although environmental and earth science cover essentially the same material, environmental science places greater emphasis on the biological realm, while earth science places greater emphasis on the physical realm.    environmental and earth science study the interactions of four major systems or “spheres” (figure 8.6).  the  geosphere  consists of the core, mantle and crust of the earth.the  atmosphere  contains all of the earth’s air and is divided into troposphere, stratosphere, mesosphere, thermosphere and ionosphere.the  hydrosphere  contains all of the solid, liquid and gaseous water on earth, extending from the depths of the sea to the upper reaches of the troposphere where water is found.  ninety-seven percent of the hydrosphere is found in salty oceans, and the remainder is found as vapor or droplets in the atmosphere and as liquid in ground water, lakes, rivers, glaciers and snowfields.  the  biosphere  is the collection of all earth’s life forms, distributed in major life zones known as biomes:   tundra, boreal forest, temperate deciduous forest, temperate grassland, desert, savannah, tropical rainforest, chaparral, freshwater, and marine.although the four systems have their unique identities, there is substantial interaction between them.  environmental scientists study the effects of events in one sphere on the other spheres. for example, a volcanic eruption in the geosphere may cause profound direct and indirect effects on the hydrosphere, atmosphere and biosphere as follows: example 1 (volcano)    on may 18, 1980, mount saint helens, in the state of washington, erupted.  this event altered the surrounding environment, and provided scientists with an opportunity to study the effects of volcanic eruptions on the geosphere, hydrosphere, atmosphere and biosphere.  such studies are vital because volcanic eruptions will continue to occur, and will have increasing impact on humans as people continue to settle lands closer to dormant volcanoes. the following are but a few of the myriad of interactions resulting from a volcanic