Which of the following statements about paleomagnetism at spreading ridges is true?

a) there is no magnetic pattern in rocks at either side of the ridge

b) rocks along the ridge shows a northward direction no mater what their age

c) the magnetic pattern on one side of the ridge is the mirror image of the other side

d) there is evidence of dramatic negative results every time the magnetic poles reverse

The true statement is that it evidences the dramatic negative results every time when the poles of the magnet get reversed.

Option D

EXPLANATION:

There are two poles: North and South Pole in Earth's magnetic field. When lava erupts at mid-ocean ridge, it cools and becomes a hard rock. During this process of cooling, the rock becomes magnetised.

Scientists have discovered that the magnetic field of Earth has been reversed in direction hundreds of times, which means that the polarity of North pole and South pole reverses.

Due to this reversal, a pattern of magnetic stripes is created in symmetry on both sides of the mid-ocean ridges.

D) there is evidence of dramatic negative results every time the magnetic poles reverse

Explanation:

Paleomagnetism is the Science that studies the magnetic field of rocks to assess changes in the Earth's magnetic field in remote times and to study the movement of continents in geological time. The studies carried out indicate that the Earth has had a significant magnetic field, at least, 2.7 billion years ago.

The magnetic field of rocks has beneficial and harmful effects on our planet. Regarding paleomagnetism at spreading ridges, there is evidence of dramatic negative results every time the magnetic poles are inverted.

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.