The answer is single opening. The gastrovascular cavity varies from the alimentary canal in that only the gastrovascular cavity has only a single opening. In addition, an alimentary canal has two openings and food moves over it unidirectional. The gastrovascular cavity is a construction establish in primitive animal phyla. It is accountable in cooperation with the digestion of food and the transportation of nutrients all over the body.
Viruses enter human body like an invader and uses the living cells to replicate causing infections in the cell or can damage it.
Explanation:
The attacks of viruses on the body of living organisms is compared with a ‘sneak attack’ as they invade the body and enters into a living cell to replicate themselves. This may cause damage or bring about changes in the cell causing sickness and infections.
They can hide themselves on our body attacking sneakily to harm the immune system to fight the infection. This stealth infection can result in fever, damaging immunity, disorder etc.
You can easily remember it because the scientific name of leech is Hirudinaria. So it secretes anticoagulant named hirudin. Which help it to feed blood longer
Answer:
Whenever matter moves from one sphere into another, some process, driven by energy, causes it to happen. Here are some examples: Water moves from a river (hydrosphere) into the air (atmosphere) by a process called evaporation.
Explanation: