Question

Why do viens have valves?

Answer 1

Explanation:

Veins have valves because the blood flows in a low pressure through the veins. Valves help the veins to prevent the blood from flowing in opposite direction.

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Answer 2

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ᴜɴʟɪᴋᴇ ᴀʀᴛᴇʀɪᴇs, ᴠᴇɪɴs ᴄᴏɴᴛᴀɪɴ ᴠᴀʟᴠᴇs ᴛʜᴀᴛ ᴇɴsᴜʀᴇ ʙʟᴏᴏᴅ ғʟᴏᴡs ɪɴ ᴏɴʟʏ ᴏɴᴇ ᴅɪʀᴇᴄᴛɪᴏɴ. (ᴀʀᴛᴇʀɪᴇs ᴅᴏɴ'ᴛ ʀᴇǫᴜɪʀᴇ ᴠᴀʟᴠᴇs ʙᴇᴄᴀᴜsᴇ ᴘʀᴇssᴜʀᴇ ғʀᴏᴍ ᴛʜᴇ ʜᴇᴀʀᴛ ɪs sᴏ sᴛʀᴏɴɢ ᴛʜᴀᴛ ʙʟᴏᴏᴅ ɪs ᴏɴʟʏ ᴀʙʟᴇ ᴛᴏ ғʟᴏᴡ ɪɴ ᴏɴᴇ ᴅɪʀᴇᴄᴛɪᴏɴ.) ᴠᴀʟᴠᴇs ᴀʟsᴏ ʜᴇʟᴘ ʙʟᴏᴏᴅ ᴛʀᴀᴠᴇʟ ʙᴀᴄᴋ ᴛᴏ ᴛʜᴇ ʜᴇᴀʀᴛ ᴀɢᴀɪɴsᴛ ᴛʜᴇ ғᴏʀᴄᴇ ᴏғ ɢʀᴀᴠɪᴛʏ.