Answer:
Explanation:
Similar to a guard at the outside of a club, deciding who should be allowed in and who to keep out, the cell membrane is semi-permeable, regulating the movement of substances in and out of the cell with the help of protein channels.
The cell membrane is a double layer of lipids (fats) and proteins that surround a cell and separates the cytoplasm/ organelles from its surrounding environment.
Answer: C. Birds moving south when the weather gets colder
Seasonal change is the change in season due to change in abiotic factors like weather conditions, sunlight availability, wind direction etc. Seasons change from summer to winter, winter to summer, summer to spring etc. These seasonal changes affect the life of biological communities including plants and animals. Some organisms adapt to changing seasonal conditions but others completely avoid them by migrating to other places where weather conditions are suitable for their survival. Therefore, birds moving south when the weather gets colder is because of seasonal change as birds cannot tolerate cold weather conditions.
1 is erosion 2 is deposition 3 is topographic map 4 is weathering 5 is constructive forces 6 is destructive forces
Dinosaur fossils had been known for centuries as "dragon bones" or the remains of giants, but it wasn't until Dean William Buckland of Oxford, England described the carnivorous "lizard" Megalosaurus<span> (in 1824) that they were formally studied as an extinct group of giant reptiles</span>
