Which type of contraction allows a muscle to produce tension without changing the angle of a skeletal joint or moving a load

Which supports the idea that birds and butterflies both have wings but they do not have a common ancestor with wings? the wings are analogous structures that evolved differently and do not have a similar internal structure. the wings are homologous structures that evolved differently and do not have a similar internal structure. wings of birds are vestigial structures, but the wing structures of bats are not vestigial. wings of bats are vestigial structures, but the wing structures of birds are not vestigial.

Which best explains why there are 64 possible codons in the genetic code and only 20 amino acids that make protiens of living organisms on earth

Where substance is produced during cellular respiration