Homologous chromosomes pair up and exchange segments of DNA.
Option A
<h3><u>Explanation:</u></h3>
Crossing over is an event of Prophase 1 of meiosis 1. It occurs in the zygotene phase of prophase 1. Here the homologous chromosome pairs get very close together and gets packed within protein coat. The enzymes randomly cut the DNA segments from both chromosomes at same loci and exchange them with each other. This results in the exchange of genes between the two chromosomes. This is how the variation comes to place between offsprings of the same individuals. The crossing over results to form X shaped intersections between homologous pair of chromosomes which is called as chaismata. This phase occurs in pachytene phase and is visible in diplotene phase when the protein coat dissolves.
Active transport is the movement of molecules against the concentration gradient from an area of high concentration to an area of low concentration, which requires energy in the form of ATP. Hope this helps! ^.^
Answer:
Lactose intolerance
Explanation:
Lactose intolerance occurs when your small intestine doesn't produce enough of an enzyme (lactase) to digest milk sugar (lactose)
James Watson and Francis Crick
Answer:
It’s C. Phenotype is an observable trait, like black fur. Genotype is not observable to the naked eye.
Explanation:
