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.
Passive transport is a naturally occurring phenomenon and does not require the cell to expend energy to accomplish the movement. In passive transport, substances move from an area of higher concentration to an area of lower concentration in a process called diffusion.
The correct answer is one of its two alleles.
Sedimentary rocks are most likely to find layers
The answer is an envelope.
A virus is an infectious agent that can replicate only inside a host cell. When it is outside the cell, it consists of genetic material coated with protein capsid. Some viruses also have an envelope which covers capsid. The function of the envelope is to identify and bind some receptor sites on the host membranes. After fusing with the cell membrane, it allows to capsid and genetic material to enter the cell and infect it.