Human eggs and sperm each contain 23 chromosomes. explain the significance of this during fertilisation in terms of chromosome numbers.

Describe at least 2 abiotic and two biotic factors found in the desert biome how do these abiotic factors interact with the biotic factors

List the advantages and disadavantages of the switch from persistent chlorinated hydrocarbon pesticides (such as ddt) to nonpersistent organophosphate pesicides. have the benefits of the switch outweighed the disadvantages? explain.

If two parents who's blood types are both b produce a child that has blood type o, what can you say about the parent's genotybes? oa) one is ii ob) one is ibi oc) both are bi od) nothing, this is impossible