A scientist crosses genes of a pine tree with broad needles (BB) with a pine tree with thin needles (tt). The F, generation of pine trees has a genotypic ratio of 100% Bt. When the scientist looks at the trees, he or she sees only broad needles. Which conclusion can be made about these trees?

Osmotic pressure is the tendency of a solution to draw water into itself across a semipermeable membrane. In osmosis, water molecules move from an area of lower solute concentration (hypotonic solution) to an area of higher solute concentration (hypertonic solution) until equilibrium is reached. The pressure generated by this movement of water across the membrane is known as osmotic pressure. Osmotic pressure is influenced by the concentration of solute particles dissolved in the solution. Solutions with higher solute concentrations have greater osmotic pressures and tend to draw water molecules from solutions with lower solute concentrations. Osmotic pressure plays a crucial role in various biological processes, including the regulation of cell volume, maintenance of fluid balance in organisms, and nutrient uptake in cells.

Exocytosis is the cellular process by which cells actively transport materials from the intracellular space to the extracellular space by fusing secretory vesicles with the plasma membrane. It is a form of bulk transport used to release molecules such as proteins, lipids, hormones, neurotransmitters, and waste products from the cell into the extracellular environment. Exocytosis plays a crucial role in various cellular functions, including secretion, communication, signaling, and membrane remodeling. The process of exocytosis involves several steps: first, secretory vesicles containing the cargo molecules bud off from the Golgi apparatus or other membrane-bound organelles within the cell. Next, these vesicles move towards the plasma membrane along cytoskeletal elements such as microtubules and actin filaments. Upon reaching the plasma membrane, the vesicles dock and fuse with the membrane, releasing their contents into the extracellular space through a fusion pore. The membrane components of the vesicles are then incorporated into the plasma membrane, allowing the cell to maintain its surface area and membrane composition. Exocytosis is essential for cellular communication, neurotransmission, hormone release, immune responses, and the maintenance of tissue structure and function.

Transcription is the process by which an RNA molecule is synthesized from a DNA template. It is a key step in gene expression and occurs in the nucleus of eukaryotic cells (and in the cytoplasm of prokaryotic cells). During transcription, RNA polymerase enzyme binds to a specific region of DNA called the promoter and unwinds the DNA double helix. One of the DNA strands, known as the template strand, serves as a template for RNA synthesis, while the other strand remains untranscribed. RNA polymerase catalyzes the formation of phosphodiester bonds between ribonucleotides, resulting in the synthesis of a complementary RNA molecule. The RNA transcript is synthesized in the 5' to 3' direction and is complementary to the template DNA strand, except that uracil (U) is used in place of thymine (T) in RNA. Transcription terminates when RNA polymerase reaches a sequence called the terminator, causing RNA polymerase to dissociate from the DNA template, and the newly synthesized RNA molecule is released. Transcription produces several types of RNA molecules, including messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA), which play essential roles in protein synthesis and gene regulation.

Cellular respiration is the metabolic process by which cells convert biochemical energy stored in nutrients such as glucose into adenosine triphosphate (ATP), the universal energy currency of cells. Cellular respiration occurs primarily in the mitochondria, which are membrane-bound organelles found in the cytoplasm of eukaryotic cells. Mitochondria are often referred to as the "powerhouses" of the cell due to their role in ATP production through aerobic respiration. The process of cellular respiration involves several interconnected metabolic pathways, including glycolysis, the citric acid cycle (Krebs cycle), and the electron transport chain (oxidative phosphorylation). In glycolysis, glucose is partially oxidized to produce pyruvate and a small amount of ATP in the cytoplasm. Pyruvate is then transported into the mitochondria, where it enters the citric acid cycle, generating more ATP and reducing equivalents (NADH and FADH2). The reduced coenzymes NADH and FADH2 donate electrons to the electron transport chain located in the inner mitochondrial membrane, leading to the production of ATP through oxidative phosphorylation. Overall, cellular respiration is essential for providing energy for cellular processes such as biosynthesis, muscle contraction, active transport, and maintenance of cellular homeostasis.