In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype, i.e. observable trait. ... Such phenotypes are often expressed by the synthesis of proteins that control the organism's structure and development, or that act as enzymes catalyzing specific metabolic pathways.
B. Covalent (Bond) I hope this helps! ^^
Evolution does not occur in a straight line with one species another in a series of orderly steps with living species that are closely related share a common trait. I hope my answer has come to your help. God bless and have a nice day ahead!
Microevolution - Allele frequency changes in a certain population over an amount of generations, it can also be simply described as "an evolutionary change in populations".
Why temperature affects heart rate in ectothermic organisms? If the temperature is within the optimal range for enzyme activity more ATP will be produced and the heart will beat faster due to increased metabolic activity and energy availability.