Suppose pcr is used to amplify a single dna marker on human chromosome 21. this is a way to identify individual chromosomes, such as paternal and maternal chromosome 21 from each parent. further suppose that a couple who have a child with down syndrome (trisomy 21) is examined for this marker. the mother has marker alleles of 310 and 380 bp. her mate has marker alleles of 290 and 340 bp. what combinations of pcr bands would be expected in their child with down syndrome if nondisjunction occurred in a. maternal meiosis i b. maternal meiosis ii c. paternal meiosis i d. paternal meiosis ii

1. describe the structure and function of the specialized cells you observed in the video. 2. research the types of cells present in the kidney.

In which layer do organisms on earth love?

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.