Humans breathe through bronchi. what structure do insects have for breathing?

a.
gills

b.
tracheae

c.
skin

d.
lungs

In general, characteristics that an organism survive and reproduce become more common over time. what mechanism of evolution causes this?

How can an organ, such as the lungs, work for multiple body systems?

Genes that come together with different alleles are heterozygous. homozygous. genotype. segregated.