answer any two of them with the use of internet if needed only.

1 sometimes when we do heavy exercise, anaerobic respiration takes place in our muscle cells. what is produced during this process?
a. alcohol and lactic acid
b. alcohol and co2
c. lactic acid and co2
d. lactic acid only

2 in each of the following questions, a statement of assertion is given, and a corresponding statement of reason is given just below it. of the statements, given below, mark the correct answer as:
a. both assertion and reason are true, and reason is the correct explanation of assertion.
b. both assertion and reason are true, but reason is not the correct explanation of assertion.
c. assertion is true, but reason is false.
d. both assertion and reason are false.
assertion: large concave mirrors are used to concentrate sunlight to produce heat in solar cookers.
reason: concave mirror converges the light rays falling on it to a point.

3 in each of the following questions, a statement of assertion is given, and a corresponding statement of reason is given just below it. of the statements, given below, mark the correct answer as:
a. both assertion and reason are true, and reason is the correct explanation of assertion.
b. both assertion and reason are true, but reason is not the correct explanation of assertion.
c. assertion is true, but reason is false.
d. both assertion and reason are false.
assertion: for observing traffic at the back, the drivers mirror is convex mirror.
reason: a convex mirror has lesser field of view than a plane mirror.

4
state one reason why exercise is important for good health.

Ireally dont know sorry

Except hold on to his or her beliefs even if there is no evidence for those beliefs.

Mantle convection  is the slow  creepingmotion of earth's solid silicate  mantle  caused by  convection  currents carrying  heat from the interior  to the planet's surface.[1][2]  the earth's surface  lithosphere, which rides atop the  asthenosphere  (the two components of the  upper mantle), is divided into a number of  plates  that are continuously being created and consumed at their opposite  plate boundaries. accretion occurs as mantle is added to the growing edges of a plate, associated with  seafloor spreading. this hot added material cools down by  conduction  and  convection  of heat. at the consumption edges of the plate, the material has thermally contracted to become dense, and it sinks under its own weight in the process of  subduction  usually at an  ocean trench.[3]this subducted material sinks through the earth's interior. some subducted material appears to reach the lower mantle,[4]  while in other regions, this material is impeded from sinking further, possibly due to a phase transition from  spinel  to  silicate perovskiteand  magnesiowustite, an  endothermic reaction.[5]the subducted oceanic crust triggers  volcanism, although the basic mechanisms are varied. volcanism may occur due to processes that add buoyancy to partially melted mantle causing an upward flow due to a decrease in density of the partial melt.secondary forms of convection that may result in surface volcanism are postulated to occur as a consequence of intraplate extension[6]  and  mantle plumes.[7]it is because the mantle can convect that the  tectonic plates  are able to move around the earth's surface.[8]mantle convection seems to have been much more active during the  hadean  period, resulting in gravitational sorting of heavier molten  iron, and  nickel  elements and  sulphides  in the core, and lighter  silicate minerals  in the  mantle.