Characteristics that give birds the energy they need to fly long distances are a. strong breast muscles and wings. b. aerodynamic feathers and lightweight bones. c. divided ventricle and air sacs in lungs. d. endothermic metabolism and fused bones.

Which way do the nitrogenous bases in dna pair up? a. a and g; t and c b. a and c; t and g c. a and t; g and c d. a and a; t and t; g and g; c and c

Describe your dna model. which part do the straws represent? the pushpins? the paper clips and the black dots you made with the marker?

Lactase is essential for digesting lactose in milk. this enzyme is specific for this sugar. why? molecules and active sites vary in size; only properly sized molecules can fit.there is a precise compatibility between the active site and the lactose molecule.specificity refers to the action of the enzyme, such as hydrolysis, and relatively few molecules can be hydrolyzed.reaction-specific enzymes assume a fit by folding around the most numerous substrate molecules.