Describe the location and function of the following structures in a frog:
$(i)$ Sinus venosus
$(ii)$ Cloaca

(N/A) $(i)$ Sinus venosus:
Location: $A$ thin-walled,triangular chamber situated on the dorsal side of the heart that joins the right atrium.
Function: It collects deoxygenated blood from the major veins of the body and pumps it into the right atrium.
$(ii)$ Cloaca:
Location: It is a small,median chamber located at the posterior end of the alimentary canal (large intestine) in a frog.
Function: It serves as a common opening for the digestive,urinary,and reproductive tracts,facilitating the discharge of faeces,urine,and reproductive cells (gametes) out of the body.