An increase in volume DECREASES the pressure in the chest (pressure and volume vary inversely when temperature is held constant -- Boyle's law). Gas can only flow from an area of higher pressure to an area of lower pressure. It can't go uphill -- ever. It can only go from high to low pressure. When the diaphragm and intercostals contract, the diaphragm flattens and the rib cage rises. That increases the volume of the chest. That increase in volume decreases the pressure inside the chest (temperature is held constant -- because the temperature of the chest cavity does not change appreciably. It remains at body temp.). Air then flows from the area of higher pressure (atmospheric) to lower pressure (intrathoracic). That continues until the pressures are equal.
When the diaphragm and intercostals relax, the chest cavity decreases in size, the pressure increases to above atmospheric, and gas flows again from the area of higher pressure (intrathoracic) to lower pressure (atmospheric) until they are again equal.
It has nothing to do with the concentration of oxygen. You can ventilate a lung with ANY gas. It has to do with the change in pressure and only the change in pressure -- which is a function of the volume of the chest cavity.
the answer is b. energy and matter can enter and leave.
Answer:
Please find the punnet square to this question as an attachment
F1 generation:
genotype = BW
Phenotype = Erminette offsprings
F2 generation:
genotype = BB (1): BW(2): WW(1)
Phenotype = 1 Black, 2 Erminette, 1White
Explanation:
This question involves a gene coding for feather color in chickens. The allele for black feathers (B) is codominant with the allele for white feathers (W) to form an erminette chicken (black and white speckles).
According to this question, a cross between a chick with black (BB) feathers and chicken with white (WW) feathers will result in an all erminette chicken (BW) in the F1 generation (see attached image)
Also, in the F2 generation got by self-crossing the Erminette genotype in the F1 generation (BW), the following genotypic and phenotypic ratios are observed:
Genotypic ratio = BB (1): BW(2): WW(1)
Phenotypic ratio = 1 Black, 2 Erminette, 1White