The skeleton of an embryo is made up of cartilage and collagen
Hope this helps :3
Recombination is the method by which organisms can randomly assort their genotypes amongst each other to create offspring with a different haplotype than either of its parents. This can be done by either copying sequences from one homologous chromosome to another (no physical exchange) or crossing over (physical exchange.
Crossing over is a mechanism in eukaryotes by which recombination can occur, in which the two homologous chromosomes contributed by both parents literally cross over and break at certain points to exchange certain sections of the chromosomes amongst each together.
Self fertilizing organisms typically do not produce offspring that are genetically identical. However, this has an inbreeding effect on its offspring, since it is recombining from the same genotype and so has a higher chance of producing homozygous offspring. This is very detrimental for mammals and some eukaryotes, but in some other organisms such as bacteria, homozygosity is typically not an issue.
The surface area to volume ratio of the cell decreases.
This decrease is due to the fact that the volume of the cell increases at a greater rate than the surface surrounding the cell, the cell membrane, increases. This change is also visible when we are blowing up a balloon.
When considering the cell division, the ratio remains roughly the same. It is advantageous for the cell to preserve its surface area to volume ratio, since a higher ratio means that substances are able to diffuse into and out of the cell at a fairly higher rate.
Depending on what you've been learning in bio so far, the glucose is used in a process called glycolysis, which basically turns the glucose into ATP (Energy) which the cell can use.
