The person should be a male.
Only male carries XY chromosomes, meanwhile female carries XX chromosomes. "Heterozygous for the X and Y chromosomes" means that the person have both X and Y chromosomes in their cells, therefore only males fits the description.
This is also why the birth rate of girl or a boy is always 50%, it is because the sex of a person is only determined by the sperm from a male. Each sperm either carries a X or a Y chromosome, never the both. Therefore, the chances of a X or a Y sperm fertilising an X egg is always 50%, also explains why both female or male must have at least one X chromosome because an egg always carry an X.
Some activities that cell requires energy may include cell division, active transport, protein synthesis etc.
In human, Cells get their energy by the food we eat. The nutrients in the food breaks down into soluble and simple molecules in stomach and small intestine and it is absorbed through the small intestine and assimilated into the cells, becoming part of it, providing the uses for each type of nutrient. And of course, many of them is the energy source.
Because as we evolve .....Some adaptation occurs according to the environment.....so the parts which are not right according to the environment and evolution become vestigial !!!
Hi,
Any kind of energy can heat our water because to make any liquid object heat you need energy.
