The Law of Limiting Factors was proposed by:

The concentration of $CO_{2}$ in the atmosphere is between

Intensity of light can be measured by

When $NaHCO_3$ is added in small quantity in an experiment showing photosynthesis,what will be the effect on it?

Categorize the following factors affecting photosynthesis into internal and external factors:
$I-$ Light
$II-$ Temperature
$III-$ Age and size of leaf
$IV-$ Leaf orientation
$V-$ Mesophyll cells and chloroplasts
$VI-$ $CO_2$ concentration
$VII-$ Water
$VIII-$ Chlorophyll content
$IX-$ Internal $CO_2$ concentration
Identify the correct sequence for internal factors and external factors respectively.

The figure shows the effect of light on the rate of photosynthesis. Based on the graph,answer the following questions:
$(a)$ In which region/s (indicated by arrows) is light a limiting factor?
$(b)$ What could be the limiting factor/s in the region where the rate of photosynthesis becomes constant?
$(c)$ What does the point where the curve flattens represent?