(21) cartilaginous fish; mouth on ventral side; hundreds of teeth arranged in adjoining circular rows; enlarged caudal fin for fast swimming

i believe it would be the lungs.

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.

i believe the answer would be b. hope it : )

correct answer: false

while planning water activities, it is very important to consider the weather, because if we do not plan and are going for a surf, then it might be that the hurricane came and drown us or may carry us to long distance from where we can not come back. there are many reasons to take information about the weather when we are planning any water activities.

hence, the correct answer would be false.