1. A heterozygous individual can produce offspring with recessive alleles.
Why does this occur?

It need to reproduce

Explanation: it has one recessive allele so whether it reproduces with another heterozygous or h mzygous the offspring could end up with that recessive allele

if the question was a recessive phenotype they would need to find another heterozygous individual to put together the 2 recessive alleles to show the recessive trait

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

this protocol provides a detailed procedure for total protein extraction for western blot analysis from achieved samples following trizol isolation of rna.