Question

give reason veins have thin flap like structure of valves​

Answer 1

Answer:

Valves are present in veins to prevent the backflow of blood as blood flows with a low pressure through the veins.

Explanation:

Valves are present in veins because blood flows through veins with low speed and low pressure which may lead to backflow of blood thus to prevent it the valve attached to the walls of the work like a stopper to create pressure and the blood does not flow back.

Answer 2

Answer:

ᴠᴇɪɴs ʜᴀᴠᴇ ᴛʜɪɴ ᴡᴀʟʟs ʙᴇᴄᴀᴜsᴇ ᴛʜᴇ ʙʟᴏᴏᴅ ɪs ɴᴏ ʟᴏɴɢᴇʀ ᴜɴᴅᴇʀ ᴘʀᴇssᴜʀᴇ ᴀɴᴅ ᴛʜᴇʏ ʜᴀᴠᴇ ᴠᴀʟᴠᴇs ᴛᴏ ᴇɴsᴜʀᴇ ʙʟᴏᴏᴅ ғʟᴏᴡ ɪɴ ᴏɴᴇ ᴅɪʀᴇᴄᴛɪᴏɴ.