Answer:
They look like X's (X shape)
Explanation:
The X shape are replicated chromosomes and are called the sister chromatids.
Answer:
Arthropods make up almost 80% of all animals; they are jointed legged animals that belong to the Animalia kingdom that include centipedes, millipedes, insects, and spiders. The success of arthropods can mainly be attributed by the following characteristics;
Presence of Exoskeleton.
The presence of exoskeleton that hardens due to the presence of chitin offers a protective cover for arthropods with different environment against advance conditions and also it protects against dehydration.
Varied habitats.
Arthropods can be found in all types of habitats from the soil, water, and land. This feature is the key to their survival since they are widely distributed hence increasing chances of survival.
Bilateral Symmetry.
Arthropods exhibit bilateral symmetry whereby a different portion of their bodies are mirror images, this form is exhibited in higher animals such as humans and dogs, and it facilitates advanced body functioning.
Jointed Legs.
Arthropods exhibit segmented legs that are jointed to allow the development of hard exoskeleton for protection. The jointed legs are specialized for grasping, jumping and running.
Short generation time.
Arthropods exhibit short generation time, which allows for faster adaptation to the environment and survival.
Reproduction strategy.
Arthropods have exhibited a sexual form of reproduction that is more successful in the growth and survival of offspring.
Segmented body.
Arthropods have a segmented body that allows for specialization of body organs and tissues, and this has promoted their success by specializing body organs to different functions.
Purines are two ringed structures
pyrimidines are single ringed structures
Earth's tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun's most direct rays. So, when the North Pole tilts toward the Sun, it's summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it's winter in the Northern Hemisphere.
