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.
There is no variety in asexual reproduction
Answer:
i think it's D
Explanation:
my bad if u get it wrong or anything
Answer:
I am 95% sure its b, if not then it is c
An insertion mutation occured.
After the mutation, a letter was inserted, and the others remained intact. The number of letters increased by 1.
