<span>When new data calls current scientific explanation into question scientists must repeat the experiments to verify results and reevaluate said scientific explanations, if necessary, based on results, then scientists can develop a new hypothesis and test that.</span>
Answer:
2. A change occurs in the environment.
4. Poorly adapted individuals have decreased survivorship.
1. Well-adapted individuals leave more offspring than do poorly adapted individuals.
3. Genetic frequencies within the population change.
Explanation:
The natural selection theory was developed by Darwin to explain how evolution occur within a population. The environment is in constant state of changes and always select for organisms that are better adapted to it.
Poorly adapted organisms gradually reduce from the population as a result of decreased survival while well-adapted individuals multiply and contribute more to successive generation.
Well-adapted individuals pass on the adaptive alleles to their offspring, eventually leading to a change in gene frequencies within the population.
Hence, the sequence of events is 2, 4, 1 and 3.
The answer is <span>c. both inside and outside of the mitochondria</span>
Answer:
All of these choices are correct.
Explanation:
Cell cycle is the process of growth and division of cell. It comprises of interphase and mitosis. In interphase the cell grows, replicates its genomic content and prepares itself for division. In mitosis the division occurs.
Cell cycle is controlled by a group of kinases called as Cyclin dependent Kinases (CDKs). They act by phosphorylating their substrates. They are of various types like Cdk1, Cdk2, Cdk4 etc. They become active when they bind to a regulatory protein called cyclin. They are also of various types like Cyclin A, Cyclin B, Cyclin C etc. Level of cyclin and corresponding CDK increases and decreases according to the stage of cell cycle. For example in S phase of cell cycle concentration of cyclin A and E shoots up. CDK2 is able to bind to these cyclin molecules and hence it becomes active.
Cell cycle has major checkpoints where the condition of cell is analysed before it proceeds to the next stage of cycle. If any abnormality is detected, repair mechanism is activated or the cell is killed. Checkpoints do not allow cell cycle to proceed in damaged cells.
p53 is a tumor suppressor protein which can halt cell cycle when it detects some abnormality in cell. It usually acts in G1/S checkpoint (before the DNA replication starts in cell) and G2/M checkpoint (before the cell division begins). Hence, all of the above statements are true.
Answer:
The correct answer would be C) It increases survival for cuckoos, but decreases survival of the other birds.
The host chicks often face lots of competition from the cuckoo chicks in terms of food as well as space. It makes it difficult for the host chicks to survive.
It has also been found that cuckoo chicks beg to be fed more intensely due to which host chick die due to starvation.
In addition, in some species of cuckoo, cuckoo chicks remove host eggs from the nest within few days of hatching.
