The right answer is vein (it contains blood and has valves).
The infra-cardiac veins of small and medium caliber possess this system of fight against gravity. The valves consist of a dense connective tissue, surmounted by endothelial cells, corresponding to a fold of the intima. They allow blood circulation in the sense organ / heart but prevent venous reflux.
In the outbreak of malaria, the frequency of the recessive allele for the HbS gene will increase. The correct option is A.
<h3>What is the HbS gene?</h3>
HbS is a beta-globin gene known as sickle hemoglobin.
It causes sickle cell disease in humans.
The disease is expressed by two HbS variants or one HbS variant or one another beta-globin gene.
Malaria is caused by the plasmodium parasite, which is present in the saliva of the mosquito.
Thus, the correct option is A, the frequency will increase.
Learn more about HbS gene
brainly.com/question/14950995
There are lots of animals that do this and they are classified as herbivores.
Answer: yup. That, and water or air.
Explanation: