An open circulatory system is characterized by the absence of blood vessels, and the haemolymph (blood-like fluid) directly bathes the tissues.
Anopheles (mosquito) is an arthropod, and arthropods have open circulatory systems.
Limax (slug) is a mollusc, and most molluscs (except cephalopods) have open circulatory systems.
Limulus (horseshoe crab) is an arthropod and has an open circulatory system.
The organisms in the other options have closed circulatory systems (Nereis, Balanoglossus, Hirudinaria, Salpa, Pheretima, Musca, Pila).
Select TRUE statements about lymph from the following:
A. Lymph vessels carry lymph through the body and finally open into larger arteries.
B. Lymph contains some amount of plasma, proteins and blood cells.
C. Lymph contains some amount of plasma, proteins and red blood cells.
D. Lymph vessels carry lymph through the body and finally open into larger veins.
The true statements are:
Name the blood vessel that brings (i) oxygenated blood (ii) deoxygenated blood, to the human heart. Also name that chamber of the heart which receives deoxygenated blood and state how deoxygenated blood from this chamber is sent to the lungs for oxygenation.
A sphere of radius R is cut from a larger solid sphere of radius 2R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is : 
AB is a part of an electrical circuit (see figure). The potential difference \(V_A - V_B\), at the instant when current \(i = 2\) A and is increasing at a rate of 1 amp/second is:
Three identical heat conducting rods are connected in series as shown in the figure. The rods on the sides have thermal conductivity 2K while that in the middle has thermal conductivity K. The left end of the combination is maintained at temperature 3T and the right end at T. The rods are thermally insulated from outside. In steady state, temperature at the left junction is \(T_1\) and that at the right junction is \(T_2\). The ratio \(T_1 / T_2\) is 