List of Figures

	Figure 1: Top: Summary of the systems that have been used to probe the constancy of the fundamental constants and their position in a space-time diagram in which the cone represents our past light cone. The shaded areas represents the comoving space probed by different tests. Bottom: The look-back time-redshift relation for the standard $Λ$ CDM model.
	Figure 2: Evolution of the comparison of different atomic clocks summarized in Table 7.
	Figure 3: Summary of the values of some coefficients entering the parameterization (70 ) and necessary to interpret the QSO absorption spectra data. From [367]
	Figure 4: Summary of the direct constraints on $αEM$ obtained from the AD (blue), MM (red) and AD (green) methods (left) and on $μ$ (right) that are summarized in Table 10.
	Figure 5: Left: Level scheme of nuclei participating to the ⁴He $(α α,γ)$ ¹²C reaction. Right: Central abundances at the end of the CHe burning as a function of $δNN$ for a $60M ⊙$ star with $Z = 0$ . From [103].
	Figure 6: (Left): variation of the light element abundances in function of $η$ compared to the spectroscopic abundances. The vertical line depicts the constraint obtained on $η$ from the study of the cosmic microwave background data. The lithium-7 problem lies in the fact that $ηspectro < ηWMAP$ . From [107]. (right): Dependence of the light element abundance on the independent variation of the BBN parameters, assuming $η = ηWMAP$ . From [105]