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:
Touching, Smelling.
Explanation:
Touching will be useful to detect stimuli like coldness and hotness.
Smelling on the other hand will help to make observations on smell and change in smell. These two are among the five senses that we use to make observations as we record what we see, hear, touch and feel, smell and taste.
Answer:
Aerobic bacteria can be used to use the available oxygen in the water to degrade the pollutants in the waste and convert it into energy it can use for its metabolic processes.
Erosion of sand n dirt and it ca cause sinkholes
