Answer:But Earth's distance from the sun doesn't change enough to cause seasonal differences. Instead, our seasons change because Earth tilts on its axis, and the angle of tilt causes the Northern and Southern Hemispheres to trade places throughout the year in receiving the sun's light and warmth most directly.Sep 23, 2019
Explanation:
Answer:
ok and what about them ??????????
<span>In marine vertebrates, the gill arches use the external gas exchange. The water holds less oxygen.
The ribs in terrestrial vertebrates have enclosed respiratory surface which is inside the body and comes as paired lungs.
Kidneys are efficient in excretion of regulation of water and nitrogenous wastes. Their reproduction is normally sexual with separate sexes.</span>
Answer: The DNA double helix is held together by two types of bonds,
covalent and hydrogen.
Explanation: Covalent bonds occur within each linear strand and strongly
bonds the bases, sugar and phosphate groups.
