What determines the similarities in anatomical features among organisms?

a ) location on earth

b) environmental conditions

c) predator-prey relationships

d) chromosomes and genes

D) chromosomes and genes

Chromosomes are long thread like structures which are found inside the nucleus of the living organisms. These chromosomes consists of small segment units called as genes. The genes control the genetic information which when expresses result in the production of specialized functional proteins. The gene is a hereditary material which is passed from the parents to the offsprings after reproduction. The expression of genes in the new organisms results in the expression of characters which were found to be similar in both parents and offsprings but some changes occur due genetic variation. Therefore, organisms exhibit anatomical similarities in features due to chromosomes and genes.  

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.

trachea, alveoli, lung capillaries, arteries