For which one of the followign observations were both lamarck's hypothesis and darwin's hypothesis in complete agreement?

The term equestrian relates to which animal? bulls cows horses pigs

Guinea pig coat color is determined by a single gene. the allele for black coat color is dominant to brown. in a cross between twoblack-haired guinea pigs, 20 offspring are born. if both parents were heterozygous, probability would predict that approximately howmany of the 20 offspring would have brown hair?

Can someone i have no idea of how to do this.