Answer:
4600-4500 million years ago, the Earth formed and its crust cooled to become solid. 4500-4400 million years ago, the oldest known thing to have formed on Earth, zircon, formed along with solid crust and oceans. 4200-4100 million years ago, the close of the Hadean Period (there are no surviving rocks).
Answer:
The correct option is<em> C) Organism A is a plant because the cells have chloroplast.</em>
Explanation:
As we can see, the organism in the slide A is multi-cellular and has chloroplast present in its cells. This means that the specimen is most likely taken from a plant. Hence, A is the correct option.
Other options, like option B, is false because nucleus can be present in animal and plant cells both. Option D is false because the cell cannot be differentiated on the basis of cytoplasm as every organism possesses a cytoplasm in which the organelles float.
Answer:
Gram staining procedure is used to differentiate between the gram-positive and gram-negative bacteria. various reagents used in the gram staining are crystal-violet, iodine, ethanol, and safranin.
1. First, the primary strain that is crystal violet is used to stain the bacterial cells present present on the slide.
2. Then the iodine solution is added over the bacterial culture and held for 1 minute. Iodine makes a complex with the crystal violet in the cell wall of bacteria.
3. Then acetone is used as a decolorizer that decolorizes the gram-negative bacteria by dissolving its lipopolysaccharide cell wall but do not decolorize gram-positive bacteria because its cell wall is made up of peptidoglycan layer.
4. The last reagent is safranin which is used to stain decolorized gram-negative cells pink. Therefore the correct order of staining is:
Crystal violet→Iodine→acetone→sefranine
The APGAR scoring is done right after the baby's birth to evaluate a newborn's condition and if needed for immediate care. If the baby is weak, inactive and grimaces. The medical team should be concerned on checking and managing the baby's pulse rate which is the measurement of heart beats per minute. For newborns, normal pulse rate ranges from 120-160 beats per minute. Another vital sign to check on the baby is pain. It is considered the fifth vital sign which is regarded as a symptom of an underlying condition and may be associated with possible or actual tissue damage.
