Most alleles of the Drosophila cut (ct) gene are stable. For example, all progeny from crossing ct1 to ct2 to yield ct1 /ct2 heterozygotes have "cut" wings. ct1 is a strong allele with severe cutting of the wings. ct2 and another allele, ctMR2, are weaker with only moderate cutting of the wings. When ctMR2 homozygotes are crossed to ct1 homozygotes, three kinds of progeny are produced, 95% have a moderate cutting of the wings (as expected for ctMR2 / ct1 ), 2.5% have wild-type wings and 2.5% have more severe cut wings like ct1 homozygotes. a) How do you explain the high frequency of reversion to wild-type? b) How do you explain the high frequency of progeny with the more severe cut phenotype?

Casts and mold are a type of preservation where the original material decays, leaving a mold in surrounding rock that can be filled with another sediment a. true b. false

Identify two examples of chemical reactions that you have encountered during the last week. identify an exothermic and endothermic reaction. explain.

Archeologists have discovered three sites showing conclusive evidence for the mastery of fire in tanzania, from a period slightly after the time that homo habilis was present in africa. these sites clearly were founded by homo erectus, the descendent species of homo habilis that migrated north, out of africa and into asia. homo erectus was known to have mastered fire, from ample evidence at sites in asia. there is no reason to attribute mastery of fire to homo ergaster, the descendent species of homo habilis that remained in africa.which of the following is an assumption on which the argument depends? (a) before their migration, homo erectus occupied african territory as far south as tanzania.(b) the strain of migration provided the selective pressure motivating homo erectus‘ mastery of fire.(c) homo ergaster would not have derived as much benefit from the mastery of fire as did homo erectus.(d) homo ergaster inherited all cultural knowledge from homo habilis, a species that did not have mastery of fire.(e) homo ergaster did not occupy regions as far south as tanzania until well after the time of these three sites.