There are 4 unknown samples that you need to identify based on your understanding of this unit. These samples include: A nucleic acid, a lipid, an enzyme and an amino acid. Here are the test results: *Nitrogen is present in all test tubes except # 1. *Hydrolysis occurs in all except #2. *Sulfur is absent in all samples except #3. *Phosphate is present in sample #4 WHAT ARE THE CONTENTS OF EACH TEST TUBE? EXPLAIN YOUR REASONING. *

To answer this question, researchers studied populations of the dusky salamander (desmognathus ochrophaeus) living on different mountain ranges in the southern appalachian mountains. the researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. four mating combinations were tested for each pair of populations (a and b)—two within the same population (female a with male a and female b with male b) and two between populations (female a with male b and female b with male a). the proportion of successful matings for each mating combination was measured. for example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). the reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (aa + bb) minus the sum of the proportion of successful matings of each type between populations (ab + ba). the table provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.

Iwill mark which of these statements best describes how nasa's kennedy space center benefits florida? it improve the average income of people. it encourages the use of science for entertainment. it produce more astronauts and space scientists in florida. it encourages people in florida to use space technology in homes.

Angiosperms are the most successful terrestrial plants. which of the following features is unique to them and account for their success? a. fruits enclosing seeds b. wind pollination c. sperm cells without flagella d. embryos enclosed within seed coats e. dominant gametophytes