<span>Leather shoes are made from natural polymers; raincoats are made from synthetic polymers. </span>
Answer: Darwin had stated in The Origin of Species that “all the organic beings which have ever lived on this Earth may be descended from some primordial form”,
Explanation:
Answer:
1. Iterative homology: e.g. antenna and leg of fiddler crab
2. Ontogenetic homology: e.g. radular teeth of veliger, feathers of chicken and hen
3. Di-polymorphic homology: e.g. white and brown feathers of hen races, chelae of male and female of fiddler crabs
4. Supraspecific: e.g. chelae of fiddler crab, chelae of lobster, feathers of hen and pheasant
Explanation:
Answer:
lungs:
The blood first enters the right atrium.
The blood then flows through the tricuspid valve into the right ventricle.
When the heart beats, the ventricle pushes blood through the pulmonic valve into the pulmonary artery.
The pulmonary artery carries blood to the lungs where it “picks up” oxygen.
It then leaves the lungs to return to the heart through the pulmonary vein.
The blood enters the left atrium.
It drops through the mitral valve into the left ventricle.
The left ventricle then pumps blood through the aortic valve and into the aorta. The aorta is the artery that feeds the rest of the body through a system of blood vessels.
Blood returns to the heart from the body via two large blood vessels called the superior vena cava and the inferior vena cava. This blood carries little oxygen, as it is returning from the body where oxygen was used.
The vena cavas pump blood into the right atrium and the cycle begins all over again.
