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.
Answer:
indigenous species are native species of a country and bred in the same country by similar species. Exotic species are species that are brought from other countries bred within same varieties or crossed with indigenous or other exotic species.
Explanation:
Cells do need food. In a process known as cellular respiration, cells convert biochemical energy (oxygen as food) from nutrients into adenosine triphosphate (ATP), and then release waste products.
hope this helps.. :D
Answer:
Decrease in genetic diversity reduces the chance of variation in the offspring.
Explanation:
If there is no variation, there will be no evolution. So, if there is a change in the environment (like an outbreak of a disease) that affects one of the organisms, it is likely to affect all of them and destroy the whole population. This would lead to extinction.
