How do arthropods ensure a fresh supply of air in the tracheal system all the times?

The sap in trees, which consists aminly of water in summer, rises in a system of capilaries of radius r = 2.5 xx 10^-5 m. The surface tension of sap is T = 7.28 xx 10^-2 N m^-1 and the angle of contact is 0^@ . Does surface tension alone account for the supply of water to the top of all trees?

You are a member of the municipal body of your town. Make a list of measures that would help your town to ensure the supply of clear water to all its residents.

These questions consist of two statement each, printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses. A. If both Assertion and Reason are true and Reason is a correct explanation of the Assertion. B. If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion. C. If Assertion is true but Reason is false. D. If both Assertion and Reason are false. Assertion: Escherichia coli, Shigella sp. and Salmonella sp. are all responsible for diarrhoeal diseases. Reason. Dehydration is common to all the diarrhoeal diseases and adequate supply of fluids and electroytes should be ensured.

Minerals absorbed by the roots travel up the xylem. How do they reach the parts where they are neede most ? Do all the parts of the plant get the same smount of the minerals?

Separation of Motion of a system of particles into motion of the centre of mass and motion about the centre of mass :- Show (dL')/(dt)=(sumr_i') xx (dp')/(dt) Further, show that (dL')/(dt)= tau'_(ext) where tau'_(ext) is the sum of all external torques acting on the system about the centre of mass.

Let A be the set of all 3xx3 symmetric matrices all of whose either 0 or 1. Five of these entries are 1 and four of them are 0. The number of matrices A in A for which the system of linear equations A[(x),(y),(z)]=[(1),(0),(0)] is inconsistent is

A spaceship is stationed on Mars. How much energy must be expended on the spaceship to launch it out of the solar system ? Mass of the space ship = 1000 kg, mass of the sun = 2xx10^30 kg , mass of mars = 6.4xxl0^23 kg , radius of mars = 3395 km, radius of the orbit of mars = 2.28 x10^8 km , G = 6.67xx10^-11 N m^2 kg^-2 .