The disease Adrenoleukodystrophy (ALD) occurs when there is an accumulation of long fatty acid chains in the body. ALD results in neurodegeneration and problems with vision, hearing, and motor coordination. In Drosophila, the bubblegum gene is similar to the human gene that when mutant causes ALD. Mutations in bubblegum result in fly vision defects. Mutations in the curly gene result in curly wings. You want to study the linkage between bubblegum and curly so you do this cross:

they both go up but then go back down. they both end lower than they started. lastly, they both are competitive/the second on.

explanation:

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!

if, i suppose that a bee stings me swinging my hand away from a bee. then that if, i persist patient when a bee or wasp areas on your surface to investigate a scent or to take h2o and i secreting heavily, the bug ultimately will move of its personal agreement. if i don't need to set for it to disappear, lightly and gently wipe it off with a part of the paper.