TASK DEFINITION: In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
PROBLEM: What are lifts?, Context: Stage lifts and orchestra lifts are specialized elevators, typically powered by hydraulics, that are used to raise and lower entire sections of a theater stage. For example, Radio City Music Hall has four such elevators: an orchestra lift that covers a large area of the stage, and three smaller lifts near the rear of the stage. In this case, the orchestra lift is powerful enough to raise an entire orchestra, or an entire cast of performers (including live elephants) up to stage level from below. There's a barrel on the background of the image of the left which can be used as a scale to represent the size of the mechanism

SOLUTION: specialized elevators, typically powered by hydraulics, that are used to raise and lower entire sections of a theater stage

PROBLEM: A deformation is also a?, Context: where  is the relevant cross-sectional area for the volume for which the stress-tensor is being calculated. This formalism includes pressure terms associated with forces that act normal to the cross-sectional area (the matrix diagonals of the tensor) as well as shear terms associated with forces that act parallel to the cross-sectional area (the off-diagonal elements). The stress tensor accounts for forces that cause all strains (deformations) including also tensile stresses and compressions.:133–134:38-1–38-11

SOLUTION: strains

PROBLEM: what is the second group of people mentioned?, Context: DNA samples from 1228 Russians show that the Y chromosomes analyzed, all except 20 (1.6%) fall into seven major haplogroups all characteristic to West Eurasian populations. Taken together, they account for 95% of the total Russian Y chromosomal pool. Only (0.7%) fell into haplogroups that are specific to East and South Asian populations. Mitochondrial DNA (mtDNA) examined in Poles and Russians revealed the presence of all major European haplogroups, which were characterized by similar patterns of distribution in Poles and Russians. An analysis of the DNA did not reveal any specific combinations of unique mtDNA haplotypes and their subclusters. The DNA clearly shows that both Poles and Russians are not different from the neighbouring European populations.

SOLUTION:
haplogroups