The communities plus abiotic and biotic surroundings is called an ecosystem
answer is : b. the universe ♡
Explanation:
During the process of prophase I, the nuclear envelope containing chromosomes has only partly broken down homologous chromosomes are joined together by proteins and a complex or pairing call synapsis- corresponding genes on sister chromatids are aligned precisely.
The syanapsis allows for crossing over which is the exchange of segments of chromosome, between non-sister homologous or similar chromatids crossing over happens at chiasmata, the point where non-sister chromosomes are joined.
Further Explanation:
All the genetic information within the eukaryotic cell is stored within the nucleus as helical DNA. This DNA is tightly wound around histones as chromosomes. In meiosis, the number of chromosomes (2n) is halved to 23 chromosomes (haploid number)through meiotic divisions, producing 4 haploid (n) germ cells or gametes (sperm or eggs), each containing half the number of chromosomes as its parent cell.
In Meiosis I
- homologs pair off into bivalents
- At crossing over: the exchange of segments of chromosome, between non-sister homologous or similar chromatids crossing over happens at chiasmata, the point where non-sister chromosomes are joined in prophase I forming bivalents; tetrads are formed.
- Spindle fibers from centrioles join sister chromatids together at their centromeres in metaphase I, pulling them to the equator of the cell;
- then, in anaphase I, while joined, they are pulled to opposite sides of the cell; the cell body splits and the nuclear envelope reforms in telophase I
In Meiosis II...
- Later, in prophase II, the nuclear envelope disintegrates and mitotic spindle fibers are formed
- independent assortment occurs. in metaphase II of meiosis: spindle fibers attach to centromeres, chromatids align independently at the equator. Genes segregate independently into new combinations as sister chromatids are pulled apart by their centromeres in anaphase II
- in telophase II the cells' nuclei and membrane are then formed with each containing the haploid number (n)
- Following the formation of gametes in the last stage, randomized fertilization occurs in sexual reproduction sperm cells fertilize an ovum to form a zygote. This occurs randomly by chance, to result in a complete set of chromosomes 2n, that is a novel combination of half each parent's number of chromosomes
Learn more about mitosis at brainly.com/question/4303192
Learn more about transcription at brainly.com/question/11339456
Learn more about DNA and RNA at brainly.com/question/2416343?source=aid8411316
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Answer:
AB
Explanation:
Blood group is discovered by famous scientist Karl Landsteiner in the year 1990. Co-dominance is the expression of the two alleles in the heterozygotes. In AB type, the two different alleles are present and they are expressed.
However in ABO type, it is govern by three allele namely A, B and O type. If only the antigen A is present, it is called A blood type. When only B antigen is present it is called B blood type and when both A and B are present, it is called AB blood type. And if neither of the antigen are present, it is called the O blood type.
The allele O is of recessive to both the blood type A and B. So a person with O blood type have two copies of O allele. But however A and B blood type are dominant of O, a person with A blood type may have one of the two genotypes -- AO or AA. Similarly, with blood type B, the genotypes are BO or BB.
Answer: Metabolic alkalosis
Explanation: Metabolic alkalosis refers to a metabolic condition in which the tissue’s pH is increased above the normal range (7.35–7.45). This occurs as a result of decrease in the concentration of Hydrogen ion, which results to increased bicarbonate in the body system. It can also be caused by direct increase in the bicarbonate concentrations.