What step of cellular respiration requires oxygen?

we need additional information in order to determine the cause of death for anna garcia. there are at least 3 things with explanation included as to why we need them are as follows:

you know they are heterozygous for a trait because they have it as jj or jj.

the wetland preservation movement began in the u.s. in earnest with the clean water act (cwa) of 1972. although not specifically written to protect wetlands, the cwa is comprised of a series of regulations designed to prevent pollutants from contaminating u.s. waters.