Another term for the programmed death of a cell is .

Which term refers to programmed cell death?a.cell death                            b.necrosisc.apoptosis

Fill in the Blank QuestionFill in the blank question.Programmed cell death, known as , naturally occurs throughout life in the brain.

Many cells die in our bodies every day by the mechanism of programmed cell death, which is known as:Group of answer choicesApoptosisPhagocytosisPyroptosisNecrosis

Programmed cell death (PCD) is involved in both cellular development and aging.  Apoptosis is a form of PCD that generally does not induce a strong immune response.  However, during another PCD mechanism called necroptosis, dying cells release molecules that promote an inflammatory immune response that can cause tissue damage.In mammals, necroptotic pathways are mediated by the RIPK3 kinase.  After phosphorylation by another kinase, RIPK3 phosphorylates the MLKL protein, which disrupts plasma membrane structure and function.  Scientists suspected that necroptosis is involved in the natural aging of the male reproductive system.  In sexually mature wild-type (WT) mice of all ages, RIPK3 expression was confirmed in testicular seminiferous tubule cells (spermatogonia and Sertoli cells) but not in testicular Leydig cells.  In an experiment, the scientists knocked out the RIPK3 gene in male mice and monitored their reproductive systems over time.Table 1 shows fertility rates of RIPK3-knockout mice (RIPK3−/−) of different ages and age-matched WT mice.  To test fertility, all males were mated with WT females of peak reproductive age (about 10 weeks old).Table 1  Effect of RIPK3 Knockout on FertilityTable 2 shows mean seminal vesicle masses and serum testosterone levels for equally sized groups of 18-month-old WT and RIPK3−/− mice.Table 2  Seminal Vesicle Mass and Serum Testosterone Levels in 18-Month-Old WT and RIPK3−/− Mice with Standard Error of the MeanThe scientists also tested for the presence of a known apoptotic marker (cleaved caspase-3 protein) in Leydig cells of 4-month-old and 18-month-old WT and RIPK3−/− mice.  Cells stained for cleaved caspase-3 were microscopically visualized (Figure 1).Figure 1  Presence of cleaved caspase-3 in Leydig cells of WT and RIPK3−/− mice.  Error bars represent the 95% confidence interval.Li, D., Meng, L., Xu, T., Su, Y., Liu, X., Zhang, Z., & Wang, X. (2017). RIPK1-RIPK3-MLKL-dependent necrosis promotes the aging of mouse male reproductive system. eLife, 6, e27692. Question 50In the experiments described in the passage, the scientists observed RIPK3 expression in cells that:release testosterone into the bloodstream.mitotically and meiotically divide into cells that ultimately become mature sperm.supply nutrients to sperm cells undergoing development.produce seminal fluid.A.I and II onlyB.II and III onlyC.I, II, and III onlyD.II, III, and IV only

Are cells alive?