When hiv initially infects a cell, the viral rna is converted into dna and then the newly formed dna is integrated into the host cell’s own dna. during this time, the infected person might feel flu-like symptoms. after the symptoms go away, the infected person may not have any other symptoms of hiv infection for many years.

Explanation:

 Regarding the HIV cycle, we fear two types of cycles: lytic and lysogenic. In the first mentioned above, the proteins that make up the capsid will replicate. These unite around the nucleic acid molecules, producing new viruses. As a result of this event, lysis occurs, that is, the infected cell breaks down and new bacteriophages are released. Symptoms caused by a virus that reproduces this way in a multicellular organism appear immediately. In this cycle, viruses use the cell's biochemical equipment (ribosome) to make their protein (capsid).

  On the other hand, there is another cycle in which the production of viral components is shut down indefinitely. This type of multiplication is called lysogeny or lysogenic cycle and is a well established phenomenon for bacterial viruses. The symptoms caused by a virus that reproduces itself through the lysogenic cycle in a multicellular organism may take time to appear. Diseases caused by lysogenic viruses tend to be incurable, such as AIDS and herpes. For this reason that after this initial symptoms, like flu, is going to disapear and other symptoms of HIV infection will lie dormant for many years.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.