Succulents are known to keep their stomata closed during the day to check transpiration. How do they meet their photosynthetic `CO_2` requirements?

What causes the opening and closing of guard cells of stomata during transpiration?

Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of O_2 root growth is restricted or completely stopped . How do the plants growing in marshlands or swamps obtain their O_2 required for root respiration?

How was path of CO_2 during carbon assimilation discovered by Melvin Calvin?

An oil company requires 12000, 20000 and 15000 barrerls of high grade, medium grade and low grade oil respectively. Refinary A produces 100,300 and 200 barrerls per day of high, medium and low grade oil respectively whereas refinary B produces 200,400,100 barrels per day respectively.If A costs Rs.400 per day and B Rs.300 costs per day to operate, how many days should each refinery be run to minimize the cost of meeting requirements.

A cottage industry manufactures pedestal lamps and wooden shades, each requiring the use of a grinding/cutting machine and a sprayer. It takes 2 hours on grinding/cutting machine and 3 hours on the sprayer to manufacture a pedestal lamp. It takes 1 hour on the grinding/cutting machine and 2 hours on the sprayer to manufacture a shade. On any day, the sprayer is available for at the most 20 hours and the grinding/cutting machine for at the most 12 hours. The profit from the sale of a lamp is Rs 5 and that from a shade is Rs 3. Assuming that the manufacturer can sell all the lamps and shades that he produces, how should he schedule his daily production in order to maximise his profit?

These questions consist of two statements each,printed as Assertion and Reason.While asnwering these questions you are required to chose any one of the following four responses. If both Assertion and Reason are true and Reason in correct explanation of Assertion. If both assertion and Reason are true but reason is not correct explanation of Assertion. If Assertion is true but Reason is false. If both Assertion and Reason are false. Assertion:Light plays an important role in process of transpiration. Reason:Light leads to potning f stomata and in dark stomata get closed.

Figure shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod =15 cm, B = 0.50 T, resistance of the closed loop containing the rod = 9.0 mOmega Assume the field to be uniform. How much power is required (by an external agent) to keep the rod moving at the same speed (= 12 cm s^-1 ) when K is closed? How much power is required when K is open? :