Now at 10 months, atlas can crawl up the steps by himself. however, once he starts walking he will have to adapt his movements and devise new strategies for the stairs, as his skills will not transfer directly from crawling to walking. this observation is most in line with

This observation is most in line with "Gross motor skills".

Gross motor skills are those which require entire body development and which include the huge (center balancing out) muscles of the body to perform regular capacities, for example, standing, strolling, running, and sitting upright. It likewise incorporates eye-hand coordination aptitudes, for example, ball abilities (tossing, getting, kicking).  

Gross motor skills are imperative to empower kids to play out each day capacities, for example, strolling, running, skipping, and play area abilities (e.g. climbing) and donning abilities (e.g. getting, tossing and hitting a ball with a bat). These are essential for ordinary self consideration abilities like dressing (where you should have the capacity to remain on one leg to put your leg into a trouser leg without falling over).

even though you have attached neither the chart nor the generalizations, i have located them online. the right answer is d, since they are asking you about a generalization. you can only infer from the chart that between 2008 and 2009 the number of employed workers decreased significantly (from over 115 millions to 107 millions approximately), which signals some type of economic crisis.