The type of reproductive barrier that occurs when two species mate but produce sterile hybrids is referred to as ________.

________ is an example of bioremediation.

Read the following scenario to answer the following questions.The earliest cells detectable in fossils were different from the cells in animals, plants, fungi, and protists living today. These first prokaryotic cells gave rise to eukaryotic cells approximately 1.7 billion years ago. The structure of eukaryotic cells today suggests how they might have evolved from their prokaryotic ancestors. Scientists examining mitochondria and chloroplasts now think that these organelles were probably free-living prokaryotes before becoming a part of eukaryotic cells long ago.Which of the following is a characteristic of mitochondria that suggests that they might have evolved from free-living bacteria?

Please read the following scenario to answer the following questions.Widow’s peak, a pointed hairline on the forehead, is a genetic trait caused by a dominant allele. It can be traced back through a family’s history using pedigree analysis.The pedigree shown here is of three generations of a family. Notice that some individuals (shown in gray) have a widow’s peak (W = dominant allele and w = recessive allele).This pedigree supports the fact that widow’s peak is due to a dominant allele, because if it were due to a recessive allele and both parents show the recessive phenotype, then ________.

What is a difference between embryonic and adult stem cells?

Which of these is a characteristic of Type I survivorship?

If seed production had never evolved, which organisms would be missing in today’s landscape?

Consider the following figure. It illustrates that a single amino acid substitution in the hemoglobin gene ________.

If adenine makes up 30% of the bases in a DNA double helix, what percent of the bases is guanine?

Please read the following scenario to answer the following questions.While working with cultured mouse cells, a researcher unknowingly treated the cells with a mutagen that causes the deletion or insertion of individual nucleotides in DNA. Subsequently, the researcher isolated and cultured a single cell from this group and noticed that the progeny of this cell were not producing a certain protein and that this affected their survival.The researcher isolated a different single cell and determined that it was producing a certain protein. However, the protein was much shorter than it should have been. What kind of mutation likely occurred in this protein?