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.
Contemporary landscapes result from many causes, including variability in abiotic conditions, such as climate, topography, and soils; biotic interactions, such as competition, mutualism, herbivory, and predation, that can generate spatial pattern even when environmental conditions are homogenous; natural disturbances. I hope this helps :)
Answer:yes of course if we don’t the environment will die and undiscovered animals will become extinct and we can’t discover them till it’s too late and those polar bears are on thin ice and it’s not fair to them that they have to suffer for our choices
Explanation:
Animals that use echolocation. Bats, whales, dolphins, a few birds like the nocturnal oilbird and some swiftlets, some shrews and the similar tenrec from Madagascar are all known to echolocate.
