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).
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.
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:
A bob of heavy mass \(m\) is suspended by a light string of length \(l\). The bob is given a horizontal velocity \(v_0\) as shown in figure. If the string gets slack at some point P making an angle \( \theta \) from the horizontal, the ratio of the speed \(v\) of the bob at point P to its initial speed \(v_0\) is :
Which of the following microbes is NOT involved in the preparation of household products?
A. \(\textit{Aspergillus niger}\)
B. \(\textit{Lactobacillus}\)
C. \(\textit{Trichoderma polysporum}\)
D. \(\textit{Saccharomyces cerevisiae}\)
E. \(\textit{Propionibacterium sharmanii}\)
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 :