D) allele frequencies of some traits change in the population
Alleles can be phenotype (how they appear) and natural selection is when an organism changes in a way that helps them survive.
It can be the way their beaks are formed that gives them a better chance of catching food among other stuff (Darwin's investigation)
Or how they change their color to adapt to the sudden change in tree coloration (Pepper moths)
The answer you are looking for is chitin.
According to a page that I found with info on the subject,
"All arthropods have bodies divided into segments and covered with a hard EXOSKELETON. This tough casing is made of a protein called chitin, which is also found in human fingernails."
https://www.factmonster.com/dk/encyclopedia/nature/arthropods
Welcome to Brainly!
You could use a line graph. Hope that helps.
Answer:
(E) left atrium.
Explanation:
Pulmonary veins are veins that carry oxygenated blood from the lungs to the heart (left atrium). These veins are part of the pulmonary circuit:
Venae cavae are a vessels (vena cava interior and superior) that carry deoxygenated blood from the body to the right atrium. From the right atrium through the tricuspid valve the blood goes into the right ventricle. Then, from the right ventricle through the pulmonary valve the blood goes into the main pulmonary artery which carries deoxygenated blood to the lungs (to recieve oxygen). Oxygenated blood from the lungs travels to the heart: two pulmonary veins from each lung to the left atrium.
