A gene encodes an enzyme, and there are two alleles of the gene. 65 units of the enzyme are required for the wild-type phenotype. Less than 65 units of the enzyme results in a mutant phenotype. One allele (A1) produces 50 units of the enzyme. A null allele (A2) produces 0 units of the enzyme. What is the phenotype of the A1A2 heterozygote

The answer is atmosphere. there are four spheres of the earth: 1. geosphere (from greek word 'geo' = ground), 2. hydrosphere (from greek word 'hydro' = water), 3. biosphere (from greek word 'bio' = life), and 4. atmosphere (from greek word 'atmo' = air). a magnetosphere is a region of space around astronomical objects controlled by the magnetic field of that object. through the process of elimination, since lightning is present in the air, it can be found in the atmosphere.

Silicon is cut into tiny pieces for computer chipslead is melted to form pelletsliquid water freezes to form ice