Definition of life.

Which pigment traveled the farthest on the chromatography paper?

The picture shows a thin layer chromatogram of an extract of leaves of annual meadow grass (Poa annua). Plastic sheets were coated with silica gel. A drop of extract was spotted at the bottom of the sheet. The sheet was then placed in a beaker of solvent [$75\%$ acetone and $25\%$ petroleum ether].

Identify the most soluble pigment.

Refer to the given figure and select the correct option regarding it.

The picture shows a thin layer chromatogram of an extract of leaves of annual meadow grass (Poa annua). Plastic sheets were coated with silica gel. A drop of extract was spotted at the bottom of the sheet. The sheet was then placed in a beaker of solvent [$75\%$ acetone and$25 \%$ petroleum ether].

Calculate the $R_f$ for phenophytin. Show your working.

Blood cholesterol levels were measured in a group of teenage boys once a month during one year. Years later, when they were adults, they were measured again in the same way. The results were recorded in the scatter graph. Each dot represents the cholesterol level as a young teenager and as an adult for each man in the study

What does this graph show about blood cholesterol levels?

The thyrotropin releasing hormone (TRH) from the $\left(1\right)$ stimulates the $\left(2\right)$ to secrete the thyroid stimulating hormone (TSH), which in turn stimulates the thyroid gland to secrete thyroxine. A $\left(3\right)$ amount of thyroxine in the blood exerts $\left(4\right)$ effect on $\left(1\right)$ so that $\left(5\right)$ TRH and TSH are produced. This eventually $\left(6\right)$ the amount of thyroxine. It is called $\left(7\right)$ feed back control.