Answer:
Molecules can diffuse across membranes via transport proteins, or they can be aided in active transport by other proteins. Organelles such as the endoplasmic reticulum, Golgi apparatus, mitochondria and peroxisomes all play a role in membrane transport.
<span>It is believed that the coelacanths and lungfish (lobed fin fishes) represent a crucial link between other fishes and tetrapods. The major feature to support the hypothesis is : </span>Their fins have skeletal and muscular structures similar to amphibian limbs.
The answer is The law of ''gravity'' helps explain why the density of air as the altitude above earth's surface increases.
Answer:
Crossing over and random alignment are the events of meiosis-I that add new gene combinations to the gametes. Random fusion of male and female gametes is called random fertilization.
Explanation:
During the pachytene stage of meiosis-I, part of the chromatids of each of the homologous chromosomes of a bivalent is broken apart and exchanged. This exchange of the genetic material between the members of a bivalent is called crossing over. The recombinant chromatids formed by crossing over have new allele combinations that were otherwise not present in the parental chromatids.
During metaphase I, the homologous pairs are aligned at the cell's equator in a random manner. This means that either the paternal or maternal chromosome of a pair may face one or the other pole of the cell. The arrangement of chromosomes during metaphase-I determines whether the paternal or maternal chromosome of each pair would be distributed to one or the other pole of the cell. This random segregation creates new gene combinations in gametes.
All the gametes have equal chances of getting fused with a gamete from the opposite gender. This is called random fertilization and further adds variations.
Answer: a crack forms, magma pushes upward, rock moves outward, magma hardens.
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Explanation: