Aclassmate tells you that a person can have type ao blood. do you agree

No, there are only four blood types determined by the presence/absence of antigens A and B (A, B, AB, 0).

A blood type-has A antigen on the surface of red cells and B antibody in the plasma

B blood type-has B antigen on the surface of red cells and A antibody in the plasma

AB blood type-has both A and B antigens on red cells but neither A nor B antibody in the plasma

0 blood type-has neither A nor B antigens on red cells but both A and B antibody are in the plasma.

relative dating involves things like higher layers are most recent than rocks lower in the sequence. this can be extended to the known sequence of fossils. rocks containing rabbit fossils are later than those containing dinosaur fossils.  

absolute dating methods mainly use radioactive elements that have known rates of decay and produce recognizable products. for example potassium 40 decays to produce argon. once a rock has solidified the argon is trapped. by measuring the argon and potassium0 you can get an accurate number for the age.  

some other methods are good for archaeological ages. dendrochronology involves recognizing the sequence of tree rings. the orientation of magnetized particles in baked clay can be used to date a fire.

hope this .. .

label a cell membrane

label b cytoplasm

label c ribosomes

label d dna

the membrane forms the outside of the cell

cytoplasm is the liquid within

ribosomes are the components within that distribute rna

the dna is the genetic make-up