Ventilation maintains a steep concentration gradient, blood at the exchange surface usually has lower O2 and higher CO2 content than the air (of for fish, the water) at the exchange surface. This is what allows for diffusion of O2 into the blood and CO2 out of the blood. Multicellular organisms have a greater number of cells so will have a higher energy demand than single cellular organisms, this demand can only be met by allowing the cells to respire, a ventilation system brings oxygen molecules which are a raw product of respiration into the hemoglobin of the blood to be transported to tissues. As surface area : volume ratio is very low so if there was no ventilation system and the organism instead relied on exchange of materials through the exposed skin it would be very difficult to met the high energy demand as less O2 and CO2 would be able to be exchanged.
Answer:
1/2 or 50%
Explanation:
Given that the extra digit is a dominant trait, the man with an extra digit may be homozygous or heterozygous dominant for the trait.
However, having a daughter with his normal wife makes him heterozygous dominant. Let's assume that the genotype of the heterozygous dominant male is "Dd" and that of his wife is "dd".
The heterozygous dominant male and homozygous recessive female would have progeny in the following ratio= 1/2 Dd (child with extra digit): 1/2 dd (child with no extra digit).
Answer:
Forces affect how objects move. They may cause motion; they may also slow, stop, or change the direction of motion of an object that is already moving. Since force cause changes in the speed or direction of an object, we can say that forces cause changes in velocity. Remember that acceleration is a change in velocity.
Explanation: