Vertebrates have all the following at some time during their development except one? .
cell wall.
nerve tube.
gill pouches.
tail

Heat from earths interior and pressure from overlying rock transform the remains of marine sediments into

Awire-hair terrier and a smooth-hair terrier are mated. the offspring produced are 6 wire-hair puppies and 2 smooth-hair puppies. a. what pattern of inheritance best describes this situation? b. what is the genotype(s) of the wire-haired puppies? of the smooth-haired puppies? c. what would be the expected genotype and phenotype ratios of a mating between 2 wire-haired terriers that are heterozygous?

Ascientific idea becomes valid when it is what?