In the absence of a nucleus, how are the functions of a sieve tube maintained?

Mention any one characteristic of the sieve tube members.

How are beta - rays emitted from a nucleus, when it does not contain electrons ?

To maintain a rotor at a uniform angular speed of 200 rad s~ 1, an engine needs to transmit a torque of 180 Nm. What is the power required by the engine? (Note: uniform angular velocity in the absence of friction implies zero torque. in practice, applied torque is needed to counter frictional torque). Assume that the engine is 100 % efficient.

How does the maximum K.E. of electron emitted vary with work function of the metal?

The activation energy of a reaction is 75.2 KJ mol^-1 in the absence of a catalyst and 50.14 Kjmol^-1 with a catalyst. How many times will the rate of reaction grow in the presence of the catalyst if the reaction proceeds at 25^@C ? (R = 8.314 JK^-1mol^-1)

How are beta -rays emitted from a nucleus, when it does not contain electrons?

Insulin and trypsin are proteins. How do they function differently?