A black hole of stellar mass is created when a massive star, exceeding 20 solar masses, runs out of nuclear fuel in its core and collapses under gravitational pressure, leading to a supernova that ejects its outer layers.
The benefit of reduced gametophytes in seed plants is that they obtain nutrients from the sporophytes. Gametophytes are tiny and can develop from spores that are kept within the parental sporophyte's sporangia. This setup shields the growing gametophyte from environmental stress, allowing it to absorb nutrients from the sporophyte.
Answer:
Sister chromatids are identical copies of chromatids from chromosomes. They are typically produced through the semi-conservative replication of a single chromosome's DNA. Thus, they can be viewed as'photocopies' of the original parental chromosomes, linked together at the centromere.
They are entirely identical in every aspect, sharing the same genes and allele configurations.
Still, minor variations can occur between the identical sister chromatids due tomutations fromerrors during replication, and differences can also arise in the lengths of telomere repeats.
Non-sister chromatids differ as they arise from separate haploid sex cells during fertilization. These chromatids come from distinct parents and possess different genetic compositions since they do not lie on the same homologous chromosomes. This is why crossing-over results in genetic variation.
However, they may still exhibit genetic similarities if they are part of homologous chromosomes. This is because Synapsis of the bivalents in these chromosomes permits the exchange of genetic material through crossing-over between non-sister chromatids, thereby sharing identical genetic traits.
Explanation:
Answer:
b. the composition of R groups varies among the 20 amino acids in proteins, which can be either polar or charged.
Explanation:
As proteins consist of numerous amino acids connected together, their connections occur uniformly across all amino acids because one segment remains identical among them all.
The remainder of each amino acid, known as the R group, differs across the various types, defining their unique characteristics and contributing to their chemical properties.
1. rivers and streams 2. groundwater seepage
