The base pairs in a dna strand are held together with hydrogen bonds. if the two nitrogenous bases in each pair were held together with covalent bonds instead of hydrogen bonds, what effect would it have on the cell? a. the cell could open and close the dna strand with less effort if the bonds were covalent. b. each time the dna strand opened the cell would need to replace the nitrogenous bases. c. the cell would have to take in and use more energy in order to break the covalent bonds. d. since the covalent bonds are unbreakable it would be difficult for the cell to make mrna.

The earth consists of a variety of different organisms. despite their diversity, however, some similarities on the structural and metabolic levels may be seen. these similarities can be attributed to a. similarities among organisms in their proteins and nucleic acids. b. the ability of organisms to readily adapt to sudden environmental changes. c. similarities in organisms' habitats and niches. d. the ability of all organisms to interbreed and produce new species.

Tara sees a commercial for a brand of pills that promise to boost energy and people perform better in work and school. as people in the commercial talk about how much better they feel when taking the pill, tara notices a message on the bottom of the screen that reads, "this pill is not approved by doctors and has not been tested in controlled experiments." what is the best conclusion that tara should make about the commercial? it is making scientific claims based on subjective observations. it is making scientific claims based on opinions instead of pseudoscientific facts. it is making pseudoscientific claims based on objective observations. it is making pseudoscientific claims based on opinions instead of scientific facts.

Which of the following best describes the relationship between glucose and complex molecules such as hormones?