RrXtXt×RrXTY is representing the cross between the white eyed female and red eyed male.
Option D
<h3><u>Explanation:</u></h3>
The genes that are discussed here both are completely dominant over their recessive alleles. In the autosome, the dominant R gene is responsible for red eye and recessive r gene is responsible for sepia eye. But in allosome, the dominant T gene allows the eye colour to be expressed and the recessive t gene doesn't allow eye colour to be expressed and makes it white.
As the female do have 2 X chromosomes and the female is white eyed, then both the chromosomes of female have t gene.
As the male is red eyed and have one X chromosome, so the male must have atleast one R gene in autosome to make the eye colour red and must have T gene in his X chromosome to make it appear in phenotype.
So the most possible cross that is given here is RrXtXt×RrXTY.
Cells with large numbers of mitochondria have a high energy demand
Answer:
At the base of Actinopterygii
*This is a unique characteristic of this group.
Explanation:
A peculiar characteristic organ observed in ray-finned fish (as well as in Sarcopterygii, or lobe-finned fish) but not in cartilaginous fish like shark is the swim bladder.
This organ is often described to be a sac containing gas. It helps these set of fish adjust its buoyancy and its position in the water by regulating the concentration of gas present in it.
The swim bladder is formed as a pouch coming off the embryonic digestive tract, and in chondrosteans and holosteans, with a set of teleosts e.g. the eels, it maintains an open pathway to the esophagus. In majority of the bony fish, the swim bladder is totally sealed off, as gas levels in their swim bladder are regulated by producing gas into the bladder via a network of capillaries, the rete mirabile (Latin word for "marvelous net").
The swim bladder is homologous to the lungs of tetrapods. Since they are formed in the same vein. Few fishes that have an open swim bladder employs it as a breathing organ.
Carbon shares 4 electrons to complete its valence shell
