Is it possible to have an inverted pyramid of energy? ? why or why not? ?

What links the two strands in a dna helix together in the middle? a. phosphate groups b. sugar rings bonded together c. proteins d. bases with hydrogen bonds

In the water cycle , when does water undergo a chemical change

Vaccines are weakened forms of disease causing microorganisms, which are given to patients to prevent disease. after the vaccine is administered, the immune system responds by creating a(n) to recognize the a.) antibody, antibiotic b.) antigen, antibody c.)antibiotic, antibody d.)antibody, antigen