In a population of humans, the frequency of straight hair is 34 percent. if straight hair is the recessive phenotype, what is the frequency of the homozygous recessive genotype?

The frequency of the recessive phenotype is also 34%
There are 3 genotypes: Homozygous Dominant, Hetrozygous Dominant, and Homozygous Recessive. There is no such thing as Hetrozygous Recessive as a Dominant trait will express it self over a Recessive.

Lets say the letter for Curly hair is H and the letter for straight hair is h.
Now lets make a legend for the genotypes
Homozygous Dominant: HH
Heterozygous Dominant: Hh
Homozygous Recessive: hh

Since straight hair is a recessive gene and is only expressed when there is no dominant gene, the genotype for straight hair is "hh"

Therefore, the frequency of the homozygous recessive genotype which is the frequency for straight hair, is 34%

Mitochondria produce atp, a high energy compound. atp is used for all sorts of enzyme-mediated reactions, such as making proteins/nucleotides/etc, certain compounds cross the cell membrane, muscles move, etc.  without this source of energy, a cell will die. it will not be able to repair itself, defend against pathogens, etc.