They are accepted as true until they are proven false. Once a theory has been tested and it is wrong, then it is no longer true.
False. <span>Adult corals are sessile organisms, i.e. they don't move around. They are tiny organisms whose shells are what we generally see.</span>
I) Locus- the chromosomal site where a specific gene is located. A locus is a fixed position on a chromosome, like the position of a gene or a marker. Each chromosome carries ,many genes; human's estimated haploid (n) protein coding genes are about 20,000, on the 23 different chromosomes.
ii) Interference; the observed double crossover frequency differs from the expected double crossover frequency. Cross over interference is used to refer to the non-random placement of crossovers with respect to each other during meiosis. It results in widely spaced crossovers along chromosomes. Interference may exert its effect across whole chromosomes. As chromosomes in many eukaryotes are large, interference must be able to act over megabase lengths of DNA.
iii) Linkage- the tendency for genes located in close proximity on the same chromosome to be inherited together. Normally when two genes are close together on the same chromosome, they do not assort independently and are said to be linked. Whereas genes located on different chromosomes assort independently and have a recombination frequency of 50%, linked genes have a recombination frequency that is less than 50%.
iv) Recombination- the process by which a new pattern of alleles on a chromosome is generated. Genetic recombination is the production of offspring with combinations f traits that differ from those found in either parent. During meiosis in eukaryotes, genetic recombination involves the pairing of homologous chromosomes. This may be followed by information transfer between the chromosomes.
Crust
mantle
convection currents
outer core
inner core
A galaxy is a group of stars, interstellar gas, dust, etc.
There are different types of galaxies. They are all categorized by their shape:
Spiral: a spiral galaxy has a disc in the centre and curved arms that come out of it.
Irregular: it does not have a specific shape. It is just a mass of things.
Elliptical: an elliptical galaxy looks basically like a disc in the universe.
I hope it helps. I tried to explain it as easy and as simple as possible!
