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.
Bacteria can convert nitrogen in the air into a form plants can use
Answer:
The endomembrane system includes Golgi apparatus, lysosomes, ribosomes, and the endoplasmic reticulum.
Explanation:
The endomembrane system has some very important function, but mostly it's on a charge of the internal transportation of "things" inside the cell. The system not only transports proteins or RNA or lipids, but it also transports what the cell no longer needs (waste). It starts with the endoplasmic reticulum close to the nucleus, where ribosomes are attached, so it receives molecules from inside the nucleus and also as proteins are synthesized in the ribosomes, therefore it also transports them to the next step which is the Golgi apparatus. The Golgi wraps molecules in a lipid layer and then they are taken to their final destination. Finally, lysosomes process big molecules and take them to a place in the endomembrane system so it can be treated as said before.
Answer:
I think the correct answer is D
