The order Cetacea includes modern-day whales, dolphins, and porpoises. These marine mammals share common characteristics that ha
ve led scientists to make a conclusion about their evolutionary history. Cetaceans: lack gills and must breathe air
give birth to live young rather than lay eggs
have fin bones that are similarly shaped to limb bones
have spines that flex up and down rather than side to side
The characteristics of cetaceans provide evidence that
The correct option is <u><em>A. they evolved from land mammals.</em></u>
Explanation:
The process of evolution explains how closely one organism is to another based on their common ancestors. Scientists believe that those organisms which show many similarities in their structures or functions might have evolved from a common ancestor in the past.
As in the above-mentioned question, scientists have observed that cetaceans lack gills and breath air, this is a property of land mammals. The cetaceans have fin bones which are similar to the limb bones. As limb bones are present in land mammals, hence they cetaceans and land mammals might have common ancestors in the past.
<span>If
ever your small boat capsizes in the swift water, all you need to do is to float
on the upstream side of the craft and never try to walk in swift water nor
stand, and this will assure your safety. Also make your feet arms widely opened
or extended with your feet pointed to the downstream.</span>
the flagellum helps the cell to move through water. Scientists think that the flagellum and the light-sensitive spot work together to increase photosynthesis. Light sensitive spot detects light.
