<span>D. evidence that are acquired through use or disuse. Since it is believed that some parts of an organism developed through its need. For example a giraffe got its long neck becuase of reaching for a tree that could produce its food. Another example is the leg of a human which developed because of its need to walk. It was believed that the parts of the an organism did exist or did vanish depending if it was no longer used or it was necessarily needed to survive.</span>
Answer:
This means that the two separate rocks were once part of one piece of rock. These layers got separated most probably by continental drift as a result of tectonic plate movements. An example of such a fossil is the Mesosaurus, a freshwater crocodile-like reptile, that is found in Southern Africa and Eastern South America continents- that means they were once one land mass.
The environment in these two separate layers would most likely be different. As the layers drift apart from each other , they drift across latitudes that are determinants of climate in a region. Therefore, even the organisms in these two rock layers will evolve differently (even though they will share a common ancestor) in adaptation to respective environments – this is called allopatric speciation.
The fulcrum is the point in any mechanical device where the moment due to weights is zero.
(Weight 1 x distance 1) - (weight 2 x distance 2) = 0
(1.7 Kg x 1.5 m ) - (weight 2 x 1.2 m) = 0
weight 2 = (1.7 Kg x 1.5 m ) / 1.2 m
= 2.1 Kg
Answer:
have curved protofilaments at their plus ends
Explanation:
Microtubules are polymers of tubulin proteins that function as the cytoskeleton of eukaryotic cells. Microtubules are dynamic structures that can grow and shrink at a rapid rate. During this process, tubulin subunits can associate and dissociate at the plus end of the protofilament. Tubulin subunits bind to two GTP molecules, one of which is hydrolyzed to GDP after assembly. When microtubules are unstable, protofilaments curl outwards because GDP-bound tubulin has a weak affinity (thereby curving it) and disassemble. The dynamic stability of microtubules is regulated by a feedback loop: when microtubules shrink, free tubulin concentration increases and microtubules start to grow. As microtubules grow, free tubulin concentration decreases and the rate of GTP-tubulin addition also decreases.
